I have an 05 Envoy SWB, 220,000 miles 4.2 4WD. Horn stopped working and when I hit the horn pad the right blinker lights up steady on the dash and front light. Additionally, when I put the right blinker on by itself, it blinks VERY fast. I discovered all this happens when the lights are on auto or manually. With the lights off everything is back to normal. Everything else seems to be ok except that I can only see my odometer and transmission displays when its dark out but that has that way for a long time - I don't think its related but thought I'd mention it. Before I go pulling fuses and what not, I thought I'd run run this by you all. It's stock with no mods.
SOLVED! Wierd electrical problem
- Thread starter tcurlee
- Start date
Mooseman
Moderator
Sounds like a ground problem associated to the lights and horn as that is probably the only thing that would be interrelated.
Electrical Ground locations
It could also be a connection issue at the plug. This guy shows how it's done however I do not recommend putting dielectric grease on it as that could actually impair the connection. Just cleaning the contacts should be enough.
Electrical Ground locations
That's likely the usual internal failure of the display in the cluster. Apparently it can be fixed.
It could also be a connection issue at the plug. This guy shows how it's done however I do not recommend putting dielectric grease on it as that could actually impair the connection. Just cleaning the contacts should be enough.
I gotta ask,,,, what exactly would pulling fuses accomplish?? I ask because I am actually curious where these sorts of things come from!
Anyway, I agree with @Mooseman this looks like a ground issue. G103 exactly. Either the ground point itself or the wiring to it.
Definitely fixable. This fix also applies to the temp/compass display in the mirror.
There are Two Distinct (oft overlooked) items worth Checking:
(1) Head Lamp Relay acting up due to the PWM (Pulse Width Modulation) problems controlling the HDM Relay may be involved here because of DRL (Daytime Running Light) issues.
(2) The MORE Likely cause here though...Is having a Faulty Dash Panel Light Switch.... remembering that it includes the Rheostat Dash Lights Dimmer Knob Feature which would affect the IPC (Instrument Panel Cluster) ...with all that "Stuff" inside that can Short Out.
THESE are the Large Selections for them available on Amazon...But RockAuto likely carries them too.
Here is another Source considering more reasons for the Cause of this problem:
www.tiresplus.com
(1) Head Lamp Relay acting up due to the PWM (Pulse Width Modulation) problems controlling the HDM Relay may be involved here because of DRL (Daytime Running Light) issues.
(2) The MORE Likely cause here though...Is having a Faulty Dash Panel Light Switch.... remembering that it includes the Rheostat Dash Lights Dimmer Knob Feature which would affect the IPC (Instrument Panel Cluster) ...with all that "Stuff" inside that can Short Out.
THESE are the Large Selections for them available on Amazon...But RockAuto likely carries them too.
Amazon.com : 2005 trailblazer headlight switch
www.amazon.com
Here is another Source considering more reasons for the Cause of this problem:
6 Possible Causes for Headlight Flickering | Tires Plus
A fluid puddle under your vehicle usually isn't a good sign especially if it's brake fluid! Learn the signs of a brake fluid leak and what to do about it.
Mooseman
Moderator
I guess meant checking fuses which now that I think about it doesn't sense in this case. --sorry, I am, however,, having a heck of a time locating G103. I found what looks like 3 ground straps (wires ) - 2 on the dr. side fender and one left firewall. Found one on the right side fender and located one under the vehicle on the frame under the driver seat area. I disconnected and cleaned them all up real well. None of that changed anything. If you could be very specific as to where I can find that G103, I would greatly appreciate it.
Mooseman
Moderator
Some More Related Turn Signal "Weirdness"...:
www.carproblemzoo.com
Perhaps GM has a TSB out there somewhere that addresses such issues?
Chevrolet Trailblazer Turn Signal Problems
Details of all Exterior Lighting/Turn Signal problems of Chevrolet Trailblazer.
Perhaps GM has a TSB out there somewhere that addresses such issues?
Mooseman
Moderator
That is a terrible web site. No solutions were documented. Seems more like a complaint log.Some More Related Turn Signal "Weirdness"...:
Chevrolet Trailblazer Turn Signal Problems
Details of all Exterior Lighting/Turn Signal problems of Chevrolet Trailblazer.
Perhaps GM has a TSB out there somewhere that addresses such issues?
Here's one where the left turn signal would kill the engine. Turned out to be a ground.
Engine quits when left turn signal is on!!!
My 02 Envoy has developoed a bizzare situation. When I turn the left turn signal on, the engine quits. I can't tell if I am losing the fuel pump or spark, the tach still registers as the engine is turning over. I turn the signal off and it will either resume running (at highway speed, it just...
gmtnation.com
And another similar issue:
SOLVED! - Electrical Gremlins
Hi All, since I bought my 02 a year and half ago I have been battling with this electrical gremlin. It only rares its head from time to time so its been very hard to track down. I have gone through all the points I can think of going over all the manuals from Mooseman and still cant fig it out...
gmtnation.com
Thanks Mooseman, I took that one off and cleaned it REAL good. It didn't change any thing. I took the horn assembly completely out of the equation - no change. bench tested it and it works fine. Would the light switch be suspect ? I ask that because the way the right turn signal flashes fast when applied and wonder if turn signals are affected by the light switch ?
Easy way to find out.. At your suspected light location with the socket harness, find the ground wire, and take a extra piece of wire, and back probe it into the socket harness (nothing permanent, just put the bare wire in the back of the harness), and ground the other end out to some bare metal. Battery or Alternator/Engine block are the best for this.
Problem fixed? The you know you still have a ground issue somewhere.
Problem fixed? The you know you still have a ground issue somewhere.
Ilikemy3s
Member
- Dec 3, 2011
- 370
Speaking of turn signal issues .. While driving at night and the headlights are on, every time i use the right turn signal, the high beams come on. Blue light on dash as well. As soon as I either let the turn signal click off or I pull the signal arm slightly back, it goes off. This does NOT happen during the day with the head lights off nor does it happen during the day with the DRLs on or off. Only at night. ??
Mooseman
Moderator
What happens with the horn disconnected? Fast flash usually means a burnt bulb but maybe in your case, it could be a short or bad ground. Thinking of another member's issue, check the wiring inside the headlight pods for burnt wiring.
In your particular case, I would highly suspect the turn signal stalk since its movement changes things. Unplug it and check operation with a meter following the schematics.
Update ..... I cleaned every ground point I could find under the hood. I'm confused on the location of ground G103. Some say on the rad. support and some say right fender by the washer reservoir I see one by the reservoir but I can find NOTHING on the support. If it really is on the rad. support, could someone point me to the exact location ?? Every one I could find I wire brushed / cleaned very well. No change. Refer to original post for symptoms. With the way things seem to change with manipulating the light switch I felt the problem was the switch. So, I got an new switch and installed it and sadly, no change what so ever. It's a Standard brand from Rockauto.
I have noticed that with the lights on normal mode, the high beams and the fog lights glow dimly as does the right turn signal on the dash that I only noticed because it was dark out.
Obviously, something is shorting but not blowing a fuse. Does anyone have any other suggestions as to what I could check next ?
I have noticed that with the lights on normal mode, the high beams and the fog lights glow dimly as does the right turn signal on the dash that I only noticed because it was dark out.
Obviously, something is shorting but not blowing a fuse. Does anyone have any other suggestions as to what I could check next ?
get a meter and start checking things. Start with the "simple issue" first .... your broken horn. Find out why it is not working... at worse, you will learn things about that and troubleshooting electrical in the truck. At best, you will come across an area that impacts more than the horn.
I "smell" a fuse box here...maybe but more likely a column issue..
I "smell" a fuse box here...maybe but more likely a column issue..
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I would be curious if the OP took a small wire, got it bolted in under the negative battery terminal main lug, and used the other end to just press against those other grounds. Does the headlight start working correctly when he does this? then you know its a ground issue. If it doesnt, then you know theres a voltage drop somewhere else.
Tankcruiser
Member
an test light would work here too when theres hi resisntance or short light will glow bright ish
It's been awhile since i started this post, time for an update. Not much has changed. I have checked and cleaned every ground point I can find. The 2 on the left fender, one one the firewall, the one on the right fender. and 4 on the engine block (left side). I can't find any others. Again, My symptoms are no horn when lights and or DRL's are on. When lights are on I get a faint glow in the high beams and fog lights and right blinker on dash. right blinker fast flashes when applied. If I manually turn off all lights my horn works. I replaced the light switch with ZERO change. If it's a ground issue I AM STUMPED ! What else can I do ? I had someone check the relays in the fuse box with a meter and they're fine.
Blckshdw
Moderator
I thought I should post an update to ground problem that was driving me crazy ! We did get it figured out , we knew it HAD to be a ground problem and we know we cleaned every ground 2 & 3 times !! G103 is on the right side fender despite what some were saying that it is on the radiator support ( at least it is on my '05 GMC ). We traced the G103 wire to a bundle of wires behind the right headlight bucket and we cut / disassembled the loom and found where like 5 or so grounds came together. Long story short, the g103 wire is compromised somewhere between that bundle and the actual ground bolt so we just ran a new wire from there down to that ground bundle and problem solved. Just crazy what a hinky ground will do !! Thanks all for your input.