Power to a swiched fuse with key off

budwich

Well-Known Member
Sorry I didn't know transmission problems affected the evap system. And since the evap code came up days before the transmission codes I figured that the evap should be addressed first. That's really crazy how there was a delay in the transmission codes.
I figured if I posted all the issues I'd be told hey let's start with 1 thing first, especially with whatever happened first.
I guess I'm learning about Chevy the hard way, I was definitely warned!

Anyway as stated in my last response to you or whoever wanted the resistance checked. It was 0.03

Sorry for the inconvenience. And Thank You for the help.
hmmmm..... OK.... how exactly did you measure the resistance? IF the value that you just stated is correct, then this is a problem. Was the key off at the time? Still further, can you redo the measurement but this time disconnect the positive battery terminal to ensure that the PCM is not being operated in any form. The valve circuit should not be reading any value of resistance or at best a very high value.

As for the impact of one system on another, I don't think we are saying they are directly related.... but if you are having powering issues, those issues can impact multiple areas ESPECIALLY if the PCM is involved. Your statement about "no other fuses are impacted" is still somewhat "suspicious"..... It is quite likely some other "power in run" circuits are also seeing "continuous power" similar to the valve circuit. You probably need to revisit / recheck "hot in run" circuits to see their power status.
 

budwich

Well-Known Member
No matter if I have the pcm in the truck or unplugged I get the same reading at the fuse box.

I would love to find the problem because its definitely there. But if I could "rig" it and it would be ok I'd be ok with that also. Only problem is I still have the transmission codes and the abs code. And if I tried to take it through inspection they'd laugh.

Plus I have alot apart, the only wires I cant see are underneath the body. I'm in the process of undoing the harness from the box to the firewall.
don't keep "ripping into things"... you will be causing yourself more problem especially on an old truck where wires are brittle along with plastics / connectors.

you need to explain exactly how you are measuring the resistance as there is something wrong with this measurement especially with the "far end of the circuit" disconnected.
 
OP
OP
Blueking25

Blueking25

Well-Known Member
don't keep "ripping into things"... you will be causing yourself more problem especially on an old truck where wires are brittle along with plastics / connectors.

you need to explain exactly how you are measuring the resistance as there is something wrong with this measurement especially with the "far end of the circuit" disconnected.
I measured in ohms, and I was told the measurements was excellent and doesn't get much better. What would be wrong with it as that measurement is close to nothing?
 
OP
OP
Blueking25

Blueking25

Well-Known Member
hmmmm..... OK.... how exactly did you measure the resistance? IF the value that you just stated is correct, then this is a problem. Was the key off at the time? Still further, can you redo the measurement but this time disconnect the positive battery terminal to ensure that the PCM is not being operated in any form. The valve circuit should not be reading any value of resistance or at best a very high value.

As for the impact of one system on another, I don't think we are saying they are directly related.... but if you are having powering issues, those issues can impact multiple areas ESPECIALLY if the PCM is involved. Your statement about "no other fuses are impacted" is still somewhat "suspicious"..... It is quite likely some other "power in run" circuits are also seeing "continuous power" similar to the valve circuit. You probably need to revisit / recheck "hot in run" circuits to see their power status.
I will recheck them before I do anything else.
 

budwich

Well-Known Member
you need to indicate exactly where you put the red lead and the black lead.
 
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OP
OP
Blueking25

Blueking25

Well-Known Member
hmmmm..... OK.... how exactly did you measure the resistance? IF the value that you just stated is correct, then this is a problem. Was the key off at the time? Still further, can you redo the measurement but this time disconnect the positive battery terminal to ensure that the PCM is not being operated in any form. The valve circuit should not be reading any value of resistance or at best a very high value.

As for the impact of one system on another, I don't think we are saying they are directly related.... but if you are having powering issues, those issues can impact multiple areas ESPECIALLY if the PCM is involved. Your statement about "no other fuses are impacted" is still somewhat "suspicious"..... It is quite likely some other "power in run" circuits are also seeing "continuous power" similar to the valve circuit. You probably need to revisit / recheck "hot in run" circuits to see their power status.
These are all the fuses. That were hot with the key off.
1 ECAS 30A
7 WRP 20A
26 TCM 10A
8 ATC 30A
9 WSW 15A
10 PCM B 20A
11 FOG LAMP 20A
12 STOP LAMP 25A
13 LTR 20A
15 EAP 15A
19 ELEC BRK 30A
21 HORN 15A
24 IPC/DIC 10A
30 A/C 10A
31 TBC 1 10A
53 HORN 15A
52 HAZRD 25A
 

Maverick

Member
Testing between the PCM and the solenoid is fruitless in my opinion, the PCM sends a ground signal to the solenoid, as far as I know, its two states are 0-off/open(no signal) 1-on/closed(to ground)

The only 12v involved is the 12v rail from battery-->keyswitch-->fusebox-->solenoid... so clearly there is 12v being introduced between there somewhere.... if you have a multimeter (obviously if you did the resistance test) if its worth more than twenty bucks it should have a continuity test/diode test... unit should beep when you touch the two leads together... can you confirm there is continuity between fuse 26 and ignition pink??

Better yet check continuity from solenoid + to ign pink, I have hard time understanding how you can have 12v on Fuse 26 with the key off and nothing on the ign pink wire
 
OP
OP
Blueking25

Blueking25

Well-Known Member
you to indicate exactly where you put the red lead and the black.
I put the red lead in the
the valve is basically a solenoid. It needs 12v and a ground to operate. In a lot of auto stuff especially GM, 12v is always there is "hot at all times" or "hot with key on". Control of the valve is done by providing a ground probably from the PCM. So just having 12v to the valve isn't a problem... its whether the ground is always there which will cause a drain.

Basically, at your "new wire", disconnect it from the fuse box and with a meter measure the resistance on that wire to a known ground (eg. battery negative or body). It should read very high. If not, you have found your drain problem.
Sorry I missed this post!
If I take the new wire( which is the orange power wire) disconnect it from the fuse box then measure resistance to the battery ground I get 190.1, 144.0, 187.3. Anywhere from 140 to 190. I can never get a constant reading to stay on the screen. But the number was always high.
 
OP
OP
Blueking25

Blueking25

Well-Known Member
you need to indicate exactly where you put the red lead and the black lead.
Sorry I missed your previous post but I just did the test.
What I had did to get that very low number was I put the red probe on E1 fuse block plug
Black probe to A pin on purge solenoid.

Then I put the red probe to pin 37 on pcm plug
And black probe on B pin on purge solenoid.
 

budwich

Well-Known Member
the resistance test that has been asked for is from the "new wire" at the fuse to ground.... if the OP did this correctly and got .3 ohms then he has a problem with his pcm BUT.... since the reading doesn't change when he disconnects the pcm... meaning the valve circuit is now open circuit, then the resistance should be infinite. He is either doing something serious wrong or he has a problem with a ground point somewhere along the route from the valve to the pcm.
 

budwich

Well-Known Member
OK.... thanks for clarification. Your tests were just checking the wiring to the pcm which is fine and explains your results. The final test that you finally did appear to show that the pcm circuitry appears to be working although I would have expect a somewhat higher reading. The fluctuation is likely a result of the pcm circuitry containing some form of capacitance in the circuit that is charging / changing. The resistance is low enough that it will indeed cause a drain with time so indeed you need to investigate the "hot with key off" at the fuse.

The list of "hot fuse" in key off is a good start.... now you need to go thru those to see if any shouldn't be on.
 
OP
OP
Blueking25

Blueking25

Well-Known Member
Testing between the PCM and the solenoid is fruitless in my opinion, the PCM sends a ground signal to the solenoid, as far as I know, its two states are 0-off/open(no signal) 1-on/closed(to ground)

The only 12v involved is the 12v rail from battery-->keyswitch-->fusebox-->solenoid... so clearly there is 12v being introduced between there somewhere.... if you have a multimeter (obviously if you did the resistance test) if its worth more than twenty bucks it should have a continuity test/diode test... unit should beep when you touch the two leads together... can you confirm there is continuity between fuse 26 and ignition pink??

Better yet check continuity from solenoid + to ign pink, I have hard time understanding how you can have 12v on Fuse 26 with the key off and nothing on the ign pink wire
Yes I I continuity from solenoid + all the way to ignition pink at the steering column.
 

Maverick

Member
Ive only got a schematic for an 03 not an 06, and maybe Im even reading it wrong, but looking at it....

If you have continuity between evap solenoid positive and ign pink, its nearly impossible to have 12v at the solenoid/fuse 26 and not have 12v at ignition pink.
 

budwich

Well-Known Member
sorry for asking about your testing but I need to get you to "restate" or "redo" some testing with respect to the voltage that you are seeing at fuse 26 with key off. With key off and the fuse 26 removed what voltage are you seeing at either of the fuse contact points in the holder? Note: please indicate where your black test lead is connected to during this test.
 
OP
OP
Blueking25

Blueking25

Well-Known Member
Ive only got a schematic for an 03 not an 06, and maybe Im even reading it wrong, but looking at it....

If you have continuity between evap solenoid positive and ign pink, its nearly impossible to have 12v at the solenoid/fuse 26 and not have 12v at ignition pink.
I just rechecked and that what I got. It beeps loud, but when I change to test voltage at pink I have nothing.
When I turn the key on I have voltage to pink then.
 
OP
OP
Blueking25

Blueking25

Well-Known Member
sorry for asking about your testing but I need to get you to "restate" or "redo" some testing with respect to the voltage that you are seeing at fuse 26 with key off. With key off and the fuse 26 removed what voltage are you seeing at either of the fuse contact points in the holder? Note: please indicate where your black test lead is connected to during this test.
I'm seeing battery voltage(its now only 12.03)and that's only at the terminal closest to the driver's side fender with the fuse pulled. Other terminal has nothing.

I tried 3 ground points.(black lead)
The ground location on the top drivers side of the firewall.
Battery ground.
And I clipped it to the door latch on the drivers side B pillar.
I get the same reading at all.

I don't mind doing things.
I really appreciate your guy's time and help greatly.
It just sucks that the fix is there but where you know.

THANKS AGAIN SO MUCH!!!!!!
 

Maverick

Member
@budwich

Do you know, is there a relay between ign pink and the 12v rail in the fuse box it powers?

Im seriously lost now if he can have 12v on evap/fuse26 but nothing on ign pink, but yet there is continuity
 

Maverick6587

Well-Known Member
@Blueking25 Could you post a reply with the picture of the wiring diagram showing your voltages with the key on and off at all of the wire connecting points on that diagram by chance?

I think it would help paint a better picture for all of us.
 

budwich

Well-Known Member
I'm seeing battery voltage(its now only 12.03)and that's only at the terminal closest to the driver's side fender with the fuse pulled. Other terminal has nothing.

I tried 3 ground points.(black lead)
The ground location on the top drivers side of the firewall.
Battery ground.
And I clipped it to the door latch on the drivers side B pillar.
I get the same reading at all.

I don't mind doing things.
I really appreciate your guy's time and help greatly.
It just sucks that the fix is there but where you know.

THANKS AGAIN SO MUCH!!!!!!
OK.... thanks..... now can you do the test one more time (with fuse removed) but this time also remove the "new wire" that was going to the valve.
 
OP
OP
Blueking25

Blueking25

Well-Known Member
@Blueking25 Could you post a reply with the picture of the wiring diagram showing your voltages with the key on and off at all of the wire connecting points on that diagram by chance?

I think it would help paint a better picture for all of us.
Please forgive me but I don't understand the question?
I don't think you mean that you want me to draw a diagram and label the voltage at each one?
Everything I test has whatever voltage the battery is at. And that's on everything I tested.
Sorry I don't understand the question exactly.
Would you please explain it differently?

Thank you
 

Maverick6587

Well-Known Member
Please forgive me but I don't understand the question?
I don't think you mean that you want me to draw a diagram and label the voltage at each one?
Everything I test has whatever voltage the battery is at. And that's on everything I tested.
Sorry I don't understand the question exactly.
Would you please explain it differently?

Thank you
No worries. I was rushing at work, sorry. I was hoping that you could use the picture I attached to this thread and use something like Windows Paint, (or whatever Apple offers if you have and Apple computer) to add the voltages see at the end of each wire at the connecting points for both the fuse attached and fuse removed readings.

This way we could see the diagram and also see what your readings are at each locations, in the same picture, without having to ask you 100 times to re-read a point.
 
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Maverick

Member
87772

Can you please also check fuses 20 23 28 29. They are on the same lead as 26 and should also have 12v with the key off according to your issue.

Also can you confirm this fuse 26 is the same in your box?
87774
 

budwich

Well-Known Member
@budwich

Do you know, is there a relay between ign pink and the 12v rail in the fuse box it powers?

Im seriously lost now if he can have 12v on evap/fuse26 but nothing on ign pink, but yet there is continuity
sorry I don't.... but the posted diagrams should help. Something is seriously amiss with the different fuse boxes that have been tried without any difference.... that points to a problem elsewhere or possibly misleading documentation... I have seen fuse designation wrong on a few occasions (in AC land as example on my 2008).

The issue here maybe a "red herring" as I do believe that if I follow the thread, the original problem was a code that was addressed / cleared by replacing a wire. My understanding is that the "next problem" (among others recently detailed) is a drain which potentially the OP is contributing to this fuse area .... BUT that maybe the "red herring".... 😄

Further, in the recent list of "HOT" fuses that he has found, the ones that you list are NOT in the list.... but worth rechecking to confirm.
 
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Maverick

Member
Further, in the recent list of "HOT" fuses that he has found, the ones that you list are NOT in the list.... but worth rechecking to confirm.
... Im so good at overlooking things haha

Agreed though, I think it might be best for the OP to remove said added wire and start re-diagnosing. Heck its worth leaving the battery unhooked for 30 and starting over, nothing quite like a fresh start/look at things.

Im curious as to how the OP 'added' this new wire, its easy enough to splice it to the + on the evap solenoid... I wonder how it was spliced on the other end to 'fuse 26', but even then its odd how 12v shows up with the fuse removed and key off
 

Maverick

Member
Ive never seen so I cant say for sure.... whats the underside of the fuse box like, how does the harness connect, is it possible two connectors are swapped around?? Would certainly cause other issues but you may not notice if you werent totally focused on only the evap circuit.

UPDATE... quick search, theres a youtube video illustrating disassembly of the fuse box... looks like the two large main harness connections could be possibly swapped around (if they arent specifically keyed) so maybe its just as simple as the OP accidentally swapped them when changing the box??
 
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Maverick

Member
### PREVIOUS POSTS NOW APPEAR TO BE IRRELEVANT ###
Fack. Just looking through my manuals again. Ive been referring back to my '03 manual for my TB, OP is an 06 doh. Obviously very different, 2006 looks like fuse 26 is a hot all the time circuit eh

87777

About 80% of the others listed here line up with the OPs hot all the time list as well.

So...... is it maybe supposed to have 12v at all times anyway?
 
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Mooseman

Moderator
Well crap. I was referring to the 2006 Rainier schematics, which I ASS-u-ME-d was the same as a TB and it shows it as switched.

So this is a complete 180 on this. Now I'm really thinking the PCM is sending ground a ground signal to the solenoid when it shouldn't. Or it's actually OK and the power draw is somewhere else.

My deepest apologies. I should have pulled out my old laptop with GM-SI and get the actual schematic for the model in question.
 

Maverick

Member
My deepest apologies. I should have pulled out my old laptop with GM-SI and get the actual schematic for the model in question.
Same I thought we could come up with a quick answer, I was using the easiest available info I had at the time.

Can the OP confirm he knows for sure 100% its the Evap solenoid causing the draw, or are we just jumping to conclusions because there was an error code, replaced the wire, and now hes noticing the drain??
 
OP
OP
Blueking25

Blueking25

Well-Known Member
No worries. I was rushing at work, sorry. I was hoping that you could use the picture I attached to this thread and use something like Windows Paint, (or whatever Apple offers if you have and Apple computer) to add the voltages see at the end of each wire at the connecting points for both the fuse attached and fuse removed readings.

This way we could see the diagram and also see what your readings are at each locations, in the same picture, without having to ask you 100 times to re-read a point.
Sorry I went back and checked I didn't see any attachments.
I'm using a Samsung Galaxy cellphone.
 

Maverick

Member
I'm using a Samsung Galaxy cellphone.
I love my Galaxy Note4, not sure Ill get rid of it anytime soon, its like a rock, but he was referring to a post earlier in the thread not that one he quoted you in..... but

Have a look at post 69, we've all unfortunately made assumptions and we were wrong... so very very wrong haha

Read through from there and let us know if you have access to a DC Amp Clamp Meter and we can track it down lickity split... If you dont own/borrow one of those it will just take a lot longer to track down.

But we should start with the basics...

Whats the condition of the battery to start with... how old is it? any green corrosion 'funk' on the terminals? cables still flexible? We should rule out an already toasted battery if you havent already done so.
 
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OP
OP
Blueking25

Blueking25

Well-Known Member
I love my Galaxy Note4, not sure Ill get rid of it anytime soon, its like a rock, but he was referring to a post earlier in the thread not that one he quoted you in..... but

Have a look at post 69, we've all unfortunately made assumptions and we were wrong... so very very wrong haha

Read through from there and let us know if you have access to a DC Amp Clamp Meter and we can track it down lickity split... If you dont own/borrow one of those it will just take a lot longer to track down.

But we should start with the basics...

Whats the condition of the battery to start with... how old is it? any green corrosion 'funk' on the terminals? cables still flexible? We should rule out an already toasted battery if you havent already done so.
Sorry I dont have a DC Amp Clamp Meter. But if it will fix this for sure I'll buy one. I have alot of money invested in this truck so far. Probably to much but it's to late.
Battery is new and terminals are as clean as new.
 

Maverick

Member
Sorry I dont have a DC Amp Clamp Meter. But if it will fix this for sure I'll buy one.
No worries Ed! Just want to be sure... did you have a chance to read post #69?? We all have the wrong info prior to that.

Fuse 26 is supposed to have 12v all the time.

Amp Clamps are about $150 or more for one that reads low enough reliably to detect parasitic draws.
 
OP
OP
Blueking25

Blueking25

Well-Known Member
No worries Ed! Just want to be sure... did you have a chance to read post #69?? We all have the wrong info prior to that.

Fuse 26 is supposed to have 12v all the time.

Amp Clamps are about $150 or more for one that reads low enough reliably to detect parasitic draws.
I just did. No big deal, shit happens. I really appreciate the time and help.

My wiring diagram says that fuse 26 is only hot in the on or run position.
From what I read and been told is that fuse 26 is definitely a switched fuse. And only should have power in the run or on position. The ignition applies power to the purge vent solenoid and it remains open until the vehicle is driven for a certain amount of time. When the computer senses there is nothing going through the evap system the pcm then sends ground to the circuit and closes the valve.

I sent a picture of the diagram, please let me know if you can see it.

Is there a specific clamp tool I should get.
 
OP
OP
Blueking25

Blueking25

Well-Known Member
No worries Ed! Just want to be sure... did you have a chance to read post #69?? We all have the wrong info prior to that.

Fuse 26 is supposed to have 12v all the time.

Amp Clamps are about $150 or more for one that reads low enough reliably to detect parasitic draws.
 

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