New to Forum and need help with my 98 Yukon

[the_coroner2002]

98 Yukon intermittent wiring issues.. need help
I recently bought a 98 Yukon and its been driving me crazy with some intermittent issues...

the details:
230K miles rebuilt trans... just a slight oil leak and a slight clunk with the rear from a dead stop... brakes are slight spongy... not horrible...

Drove fine the first day for 2 hours.....

Day 2 then it rained I noticed a clicking coming from the left cowl near the left lower dash area and the service 4 x 4 light was coming on and off...

The same day the ABS pump was coming on and the left front brake was doing the abs thing...

I unplugged the abs fuse under the hood to keep it from coming on repeatedly to try and diagnose the issue...

Then the truck started to lose the speedo and the throttle was intermittent and breaking up... also intermittent and was fine the next am...

So I scanned the OBD II and no codes there.

Yesterday when I was adjusting the tilt wheel...

The service 4 x 4 light and abs light were flashing and the 4 X 4 switch was lighting up all over the place... every time the wheel was adjusted all the way down the lights would go crazy on and off... then when I put the wheel up they went off...

Sorry for the long post but this truck is giving me a WTF moment...

So where do I start? I thought It was a simple abs sensor issue.. common or 4X4 switch.. also common. but with the steering column issue now I am stumped... cause when they are not acting crazy the truck runs like a top...

Figuring abs sensor/hub one side or another... but what is the deal with the the column issue... do I take the column harness apart and clean and re-grease it? The speedo issue and throttle issue? please help you guys are the best and all have experience with these things...

Also I am in CT and am looking for a local GM service tech to take my stuff to who wont give me the high hard one in the rear...

Im a member of GMFullsize as well but no help there... seems like a better chance of me getting an answer on here....

Thanks in advance for any advice or help guys... much appreciated

 

[JBLEEZE33]

have you looked under the dash to make sure the wires are not being pinched or shorted out in anyway causing them come off and on...

 

[SunlitComet]

Have you had any actual shorts that a required a fuse replacement?

 

[the_coroner2002]

No shorts that required fuses being blown and I cant really see the harness for the column from under the dash cause its so far up in there.

I have been thinking it may be the multifunction switch because it all is related and they are supposedly prone to failure.

I am gonna try to take it to a local shop I found thru GMFullsize and at least have the Drive Train sensors scanned to narrow it down.

It could be a combination of more than just one thing. Weird how they are all happening with that column being adjusted and it seems that they are all connected at some point...

FYI I found a site with the MFs switch for like 68 bux even thought I could get it thru work... the site also included a video detailing the steps on replacing the part and the tools required as well... nice for saving me 10 trips to the tool box! or worse the parts store...

http://www.1aauto.com/1A/cruise-control-lever/GMC/C2500-Truck/1AZCC00007/473434/1997?utm_campaign=gb_api_br&year=1997&utm_medium=comparisonshopping&utm_source=google_base&utm_content=ZCC

 

[SunlitComet]

Would leave the multi-switch alone for now. I would actually go after bad grounds first.

In addition:

The clicking sound your are probably hearing the 4x4 system doing a self test of the t-case motor and brake and failed because it is not seeing a reaction to the tests. And abs activates sometimes because of a dirty sensor. But the one thing that ties all this things together including a speedo error is a vehicle speed sensor or it wiring and how the vehicle speed sensor so I would look for the sensor at the tail end of your tranny looking for loose, corroded or broken terminals, wires or sensor component. If nothing there there is a dark green wire from the dash cluster that runs in the dash heading out o the computer that may be shorting out.

---------- Post added at 07:26 PM ---------- Previous post was at 07:19 PM ----------

Remember that while the moving of the steering column may trigger the problems it does not really have wiring in it related abs, speedo or 4x4 system with the exception of the ignition switch switching power to them.

 

[the_coroner2002]

Update with the truck. Ive only really driven it about 3 times in the past 2 weeks locally about 10 minutes at max. The guy I purchased the truck from stated that the trans was rebuilt recently but has no paperwork. LAST NIGHT I went into town about 5 miles and lost 3rd and 4th gear. I got on the highway and it took a while to upshift to second and no 3rd and no O/D either. Just lots of balls out in second gear untill I could turn around at the next exit and get it back to the garage. Its hard to tell because it was dark and late but I wasnt seeing any fluid on the stick.

I will get underneath after it stops raining and check the fluid and the connectors on the speed sensor. I was thinking bad ground as well or maybe broken sensor /connector or pinched harness... I was thinking of taking it local on tues and having the drivetrain scanned because ive had the abs fuse out for the past two trips to town.

I appreciate the info and the green wire issue. Ill keep you guys up to date.

 

[the_coroner2002]

It was raining yesterday so at least I was able to get under the hood, checked out the harness to the ECM and saw the white wire going in to the white side of the connector was broken/burnt. Repaired the wire and looked under the dash. Saw 2 wires zip tied that were looking suspect as something added recently. saw they were wrapped around the power wire coming from the fusebox. RIGGED with no connectors just ghetto rigged wires and tape. while just touching them the dash was clicking. so they are getting traced and fixed or removed now.

 

[SunlitComet]

What color of ecm plug was the wire on? I could tell you what it is. The pcm calls them, black, red, clear, blue. The whites under the dash could be related to the the brake light activation, interior lighting control or door locks.

 

[the_coroner2002]

it was on the connector labeled white, Its on the right side of the pcm if your looking at it with the connectors facing you. the wire itself was white. the wires under the dash were grounding out on the column and they were for fog lamps. Every time I touched the harness under the dash where they were rigged to the dash clicked like crazy. i got rid of them altogether. trans is leaking at the shaft and it was low on fluid, i added some and lets see what happens when i test drive.

 

[SunlitComet]

I will assume the manual meant white instead of gray for the manuals sake. Probably a typo. At any rate that is the ignition timing signal from the ignition control module next to the coil. It goes to the pcm and if cut completely would cause a no start condition.

Diagrams show there is no solid white wire associated with fog lamps. So you may want to trace both ends one day. Or look for other things wrong you might have missed.