This is kind of a strange one. Inherited 2008 Saab 9-7X I've been slowly bringing back to life. When I pull the ebrake lever I don't get any light on in the dash saying the the ebrake is on, I've never been in a car that didn't have that, im assuming this is supposed to have one? Normally wouldn't care, but front TPS wont show pressure and im trying to get it into programming mode and no matter what I do it just wont do it, im wondering if its because it thinks the ebrake isn't on. I also have a few other electrical gremlins around that area, I need to keep the radio fuse pulled or it dies in about 3 days, and the rear seat radio/hvac controls are completely inoperative. I assumed those two things just needed replacement but could all that be related somehow? Thanks!
Cant get truck into TPS programming mode, dont think it knows ebrake is on?
- Thread starter Benson86
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xavierny25
Member
Luckily for you, you pretty much have our member @Blckshdw down the road from you if you need any help in those areas (electrical gremlins).
I dont have the schematics on hand right now but I'm pretty sure there is a switch connected to the ebrake that would make that light come on in the dash. Maybe a spilled drink dried up and has made it's way there and the switch is stuck. Or you may have other electrical issue going on since the radio is killing the battery.
You could just go to a tire shop and have them program that tire pressure sensor.
I dont have the schematics on hand right now but I'm pretty sure there is a switch connected to the ebrake that would make that light come on in the dash. Maybe a spilled drink dried up and has made it's way there and the switch is stuck. Or you may have other electrical issue going on since the radio is killing the battery.
You could just go to a tire shop and have them program that tire pressure sensor.
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Blckshdw
Moderator
I've attached the wiring diagram from @Mooseman signature here, this should help you narrow down where to troubleshoot for the parking brake issue.
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Mooseman
Moderator
A tire shop wouldn't be any more able to program it unless the parking brake switch is working. Unfortunately, this will likely mean having to pull the center console. First, check that the main connector is plugged in correctly. Remove the center console storage bin and check the connector. The fact that your rear panel isn't working might be pointing here.
xavierny25
Member
Interesting, even with the tool to do the work on the tpms you have to have the ebrake applied. I don't recall the tech applying the ebrake when they used there tool to reprogram each sensor on my truck. Then again it was like 5-6yrs ago when I had Mavis replace all 4 tires. Since then my brother has been the one to replace my tires and I've done the relearn with the steps shown in the manual.
Mooseman
Moderator
All the programmer does is activate the sensors without having to deflate the tires manually. You still have to get the vehicle into programming mode and go to each wheel with the tool unless there is an uber tool that accesses programming through the OBD port. I have both a cheap one from Amazon and a more expensive one and they both work the same way except the expensive one also reads the sensor's data being transmitted.
instead of digging into the console, and since the rear box may have issues already, based on the posted diagram, locate the jumper point at the rear box. take a meter and measure resistance toward the brake switch with the brake off and then set and see if you notice anything. IF not, obviously the problem is in that direction. Do the same resistance measurement in the other direction (battery disconnected but ground attached). You should see something. If not, then you likely have a problem towards the bcm. Go from those results. IF you are draining batteries, an unhappy bcm is a candidate.
Interesting, that diagram is super helpful. And what your saying Budwich makes sense on how to test. I would honestly be happy if these issues were all BCM related that's an relatively easy fix. Thanks!
m.mcmillen
Member
You should be able to use a tech2 to get it into programming mode. I’ve never done it on a Trailblazer but I have on other GM stuff.
Can I ask for a little clarification what you mean by the jumper point? As far as I can tell the parking brake sensor doesn't go through a fuse, so where would I test? I can't see a point where the wires enter the box, only exit the BCM. Do I have to take the whole box out? Thanks!
probably have to pull the top "layer". But since you indicated possible issues with the rear box, it will give you an opportunity to look at things there first. If its easier for you at this point, you can do the "complete check" at the BCM connector instead BUT then if the check fails (ie. you don't see any difference between brake set and not set), you would still need to go to the jumper point at the rear box. I guess it depends on how or what you want to tackle first or which has easier / quicker access.
Well here's something new to add to this. Today when I was driving the check your gauges light came on and the water temperature gauge had completely stopped reading. Showing all the way at the bottom. Car is working fine and temps all seem fine. Does the BCM control that as well? Could that be another symptom of that failing?
m.mcmillen
Member
Aaaand just to add to the fun, the CEL came on on the way into work this morning. Will pull codes when I get back home and post.
