2003 GMC Yukon XL Need Help tracking down an issue

[Yukon_doit]

Hello All. This is my first post, so if I am doing anything wrong please let me know! Excited to be a part of this forum and hopefully find some answers about my truck. For starters I own a 2003 GMC Yukon XL "Southern Comfort" Edition.

I purchased this truck July of 2018. I found it 2 hours away from my home and got it for a killer deal. Needed minimal work, things like brakes all around, front wheel bearings/hubs, transmission service (truck had a nasty slip from 2nd into 3rd, replaced EPC solenoid and it seemed to get rid of the problem...for now). Well here we are almost 6 months later and I've developed a couple new issues that have me completely stumped.

The driver heated seat never worked from the day i bought it. I wasn't too worried about it because it was summer when i purchased the truck. Now that winter is rearing its ugly head I have been trying to get to the bottom of this. The seat clicks on for maybe 2 seconds and them shuts itself off. From the research I've done so far, it sounds like the heating element within the seat is bad, forcing the seat to turn off. But in the last week the seat has developed a new problem. The power seat controls have somehow reversed controls (ie. meaning if i want to move the seat back i must move the seat control forward). The heated seat will randomly try and turn itself on while driving and as stated before it wont stay on long. So i'm getting a relay click from under the dash about 20 times a minute from this seat malfunctioning all while the seat is turning on and off rapidly. I also read somewhere that the switch on the door panel can be affecting the operation of the heated seats as well as a failed module under the seat. Can anyone provide input on this issue?

Another issue is that the power window switch on the drivers side has failed and will no longer roll up the driver rear window. The replacement part is about $250 from the dealer in my area and they said it needs to be programmed once the new switch is installed? Can anyone confirm or deny this?

Last problem i seem to be having is with the 4wd. 4wd works great, low high and auto. The issue I'm having is once you use 4wd and go back to 2wd everything disengages fine, but about 5 miles down the road the "service 4wd" message comes on the driver info screen. No noises or weird feelings from the driveline. Only comes on once and never comes on again until you use 4wd next. This isn't too big of an issue for me as I will rarely be using 4wd. Will be mainly using it for Surf Fishing in the Summer on the beach. Just seeing if anyone has had an issue similar to me and has found a solution.

Any help is greatly appreciated! This stuff has been bothering me for a while now so I figured I would reach out to fellow Yukon/Tahoe owners to try and find some answers. Like I said I'm a newbie so if i posted this in the wrong section, please let me know! Thank in advance!

 

[CountryBoy19]

Hello All. This is my first post, so if I am doing anything wrong please let me know! Excited to be a part of this forum and hopefully find some answers about my truck. For starters I own a 2003 GMC Yukon XL "Southern Comfort" Edition.

I purchased this truck July of 2018. I found it 2 hours away from my home and got it for a killer deal. Needed minimal work, things like brakes all around, front wheel bearings/hubs, transmission service (truck had a nasty slip from 2nd into 3rd, replaced EPC solenoid and it seemed to get rid of the problem...for now). Well here we are almost 6 months later and I've developed a couple new issues that have me completely stumped.

The driver heated seat never worked from the day i bought it. I wasn't too worried about it because it was summer when i purchased the truck. Now that winter is rearing its ugly head I have been trying to get to the bottom of this. The seat clicks on for maybe 2 seconds and them shuts itself off. From the research I've done so far, it sounds like the heating element within the seat is bad, forcing the seat to turn off. But in the last week the seat has developed a new problem. The power seat controls have somehow reversed controls (ie. meaning if i want to move the seat back i must move the seat control forward). The heated seat will randomly try and turn itself on while driving and as stated before it wont stay on long. So i'm getting a relay click from under the dash about 20 times a minute from this seat malfunctioning all while the seat is turning on and off rapidly. I also read somewhere that the switch on the door panel can be affecting the operation of the heated seats as well as a failed module under the seat. Can anyone provide input on this issue?

Another issue is that the power window switch on the drivers side has failed and will no longer roll up the driver rear window. The replacement part is about $250 from the dealer in my area and they said it needs to be programmed once the new switch is installed? Can anyone confirm or deny this?

Last problem i seem to be having is with the 4wd. 4wd works great, low high and auto. The issue I'm having is once you use 4wd and go back to 2wd everything disengages fine, but about 5 miles down the road the "service 4wd" message comes on the driver info screen. No noises or weird feelings from the driveline. Only comes on once and never comes on again until you use 4wd next. This isn't too big of an issue for me as I will rarely be using 4wd. Will be mainly using it for Surf Fishing in the Summer on the beach. Just seeing if anyone has had an issue similar to me and has found a solution.

Any help is greatly appreciated! This stuff has been bothering me for a while now so I figured I would reach out to fellow Yukon/Tahoe owners to try and find some answers. Like I said I'm a newbie so if i posted this in the wrong section, please let me know! Thank in advance!

IMHO, your problems can be mysterious snd costly to repair when you're shooting in the dark. Get yourself one of the $300 GM Tech 2 scan tools and find the actual problem. The driver seat module will tell you why its shutting off the seat, the transfer case control will tell you why it needs service, and any modules that need programming can be done with the Tech 2, the included software, and a laptop.

 

[swathdiver]

Mark is right Dave, you're going to need a Tech2 to diagnose these problems and program any new modules needed. You'll also need the shop manual, either via subscription through ALLDATADIY or buy the disc/download from SeriousCTBuyer on ebay. I like to have both.

If you poke around this forum you'll find the reverse switch posts and some of the others but a bi-directional scan tool is essential.

 

[Doubeleive]

well without dropping 3 bills on a scanner, you can check and inspect your seat/switch harness and seat heater harness under the carpet, look for any corrosion or anything that looks burnt, it's common for this to be at least part of the issue, sometimes the heater wires get shorted under the seat cover also, some people repair them others replace them, could be a bad seat switch as well, the issue is not unusual if you search the forum you will others that have had the same issue and what they did to fix or repair it.

4wd could be the encoder motor is sticky (maybe) could the be the dash switch too or wiring down at the transfer case or front diff. or something completely different just a couple things to take a look at that also do not cost anything.

doesn't cost anything but time to look and check stuff out sometimes it's not the fastest method but occasionally you get lucky and no cost out of pocket

 

[-DIRTBAG-]

On my 07 Tahoe, the passenger side seat switch was giving my wife fits. Sometimes it would work, sometimes it wouldn't. She likes to be able to recline on long road trips and it was pissing her off. LOL I took the switch from the drivers side seat and installed it in the passenger side and it was fixed. It was an easy way to know if the switch was the issue or the actual motors in the seat itself. Hope that helps, maybe.

 

[UrbanSuburban]

I very much fall on the get the Tech 2, its a bargain considering what it used to cost, it will pay for itself over and over. These vehicles have over 15 computers on them and with a Shop manual or all data you are armed to the teeth for anything. Now as far as your seat is concerned. Try pressing just the seat back and see if it stays on, then its just the seat bottom that needs replacing. Dorman makes them and its very popular. If the seatback does not work either then you are going to have to do some dianostic work. Good Luck

 

[UrbanSuburban]

I very much fall on the get the Tech 2, its a bargain considering what it used to cost, it will pay for itself over and over. These vehicles have over 15 computers on them and with a Shop manual or all data you are armed to the teeth for anything. Now as far as your seat is concerned. Try pressing just the seat back and see if it stays on, then its just the seat bottom that needs replacing. Dorman makes them and its very popular. If the seatback does not work either then you are going to have to do some dianostic work. Good Luck

 

[CountryBoy19]

well without dropping 3 bills on a scanner, you can check and inspect your seat/switch harness and seat heater harness under the carpet, look for any corrosion or anything that looks burnt, it's common for this to be at least part of the issue, sometimes the heater wires get shorted under the seat cover also, some people repair them others replace them, could be a bad seat switch as well, the issue is not unusual if you search the forum you will others that have had the same issue and what they did to fix or repair it.

4wd could be the encoder motor is sticky (maybe) could the be the dash switch too or wiring down at the transfer case or front diff. or something completely different just a couple things to take a look at that also do not cost anything.

doesn't cost anything but time to look and check stuff out sometimes it's not the fastest method but occasionally you get lucky and no cost out of pocket

That is all very true... you can often replace financial costs with time-costs. That being said, almost all circuit failures (shorted/broken wires) will be detected by the control module that operates that circuit and will trigger a code. This will greatly simplify the process of tracking down exactly what the problem is (you may still have to check the wires for breaks/shorts, but at least you would know that IS the problem according to the codes). My scanner, at only a couple months old, has proven itself more valuable than the $308 I paid for it. It's been a truly invaluable tool.

IE, the scan tool will trip a code and tell you specifically what circuit is faulty with the seat heater. When I thought I had a heater going out, and before I realized the scanner would drill down that far into the modules, I tried troubleshooting a suspected faulty seat heater bottom. I found the little green plug, unplugged it, ohm'd the circuit out, etc. Then I tried to turn the heated seat on (not realizing they are "smart") so I could see if I was getting voltage at that plug. The lights flashed and it went back off. I thought I fried something. I got the scanner out and started checking around and voila, "Lower, passenger seat heater circuit failure"... plug it back in, clear the code and heated seat worked fine... As it turns out, it was operator error, I never tested for myself that the bottom heated seat wasn't working, I took my wife at her word. She was only pushing the button for "upper only" heat... she now knows how to operate the buttons and no problems...

I very much fall on the get the Tech 2, its a bargain considering what it used to cost, it will pay for itself over and over. These vehicles have over 15 computers on them and with a Shop manual or all data you are armed to the teeth for anything. Now as far as your seat is concerned. Try pressing just the seat back and see if it stays on, then its just the seat bottom that needs replacing. Dorman makes them and its very popular. If the seatback does not work either then you are going to have to do some dianostic work. Good Luck

Just because the back comes on doesn't mean the bottom is faulty. The power wires for the bottom plug into the back. A faulty plug/wire in the back (that feeds power to the bottom) can cause a fault. IE, Driver seat control module plugs into upper (back) seat heater, lower seat heater plug into upper seat heater. A fault in the circuit between those 2 plugs can make it appear there is a faulty lower heater, when in fact, it could be a circuit failure in the upper heater that only effects the lower heater circuit.

 

[UrbanSuburban]

Agreed, but when I was researching my heated seat problems, on the forums, over and over it was the advice given to check the seat back and if not then you have to do the full diagnostic. The drivers side seat bottom is very common to burn out.

 

[BigDogYJ]

Honestly before you start spending money on modules and programming and such, start with checking wiring. These trucks are getting to the age where the wires in the door harness are getting old and breaking down from opening and closing all the time. I have 3 family members/friends with similar vintage trucks (as well as myself) 2001-2005 Yukon xl and suburbans and all of us have had to repair a broken wire or 2, especially in the driver door harness. its not a hard job, just gets a little tricky getting access to it. but I would look there first.

Actually while I type this, I know I have one on the passenger side that I need to address soon. when the back passenger door is open the lights come on, then its as if the truck thinks the door is closed even though its wide open, when I start closing it, it changes and thinks its open right before I close it. That to me, screams, shorted/broken wire.

If you have time and not a ton of cash to throw at it, start there. Its cheap and pretty easy if your handy with wire strippers/crimpers, etc.

 

[Chris North]

Hello All. This is my first post, so if I am doing anything wrong please let me know! Excited to be a part of this forum and hopefully find some answers about my truck. For starters I own a 2003 GMC Yukon XL "Southern Comfort" Edition.

I purchased this truck July of 2018. I found it 2 hours away from my home and got it for a killer deal. Needed minimal work, things like brakes all around, front wheel bearings/hubs, transmission service (truck had a nasty slip from 2nd into 3rd, replaced EPC solenoid and it seemed to get rid of the problem...for now). Well here we are almost 6 months later and I've developed a couple new issues that have me completely stumped.

The driver heated seat never worked from the day i bought it. I wasn't too worried about it because it was summer when i purchased the truck. Now that winter is rearing its ugly head I have been trying to get to the bottom of this. The seat clicks on for maybe 2 seconds and them shuts itself off. From the research I've done so far, it sounds like the heating element within the seat is bad, forcing the seat to turn off. But in the last week the seat has developed a new problem. The power seat controls have somehow reversed controls (ie. meaning if i want to move the seat back i must move the seat control forward). The heated seat will randomly try and turn itself on while driving and as stated before it wont stay on long. So i'm getting a relay click from under the dash about 20 times a minute from this seat malfunctioning all while the seat is turning on and off rapidly. I also read somewhere that the switch on the door panel can be affecting the operation of the heated seats as well as a failed module under the seat. Can anyone provide input on this issue?

Another issue is that the power window switch on the drivers side has failed and will no longer roll up the driver rear window. The replacement part is about $250 from the dealer in my area and they said it needs to be programmed once the new switch is installed? Can anyone confirm or deny this?

Last problem i seem to be having is with the 4wd. 4wd works great, low high and auto. The issue I'm having is once you use 4wd and go back to 2wd everything disengages fine, but about 5 miles down the road the "service 4wd" message comes on the driver info screen. No noises or weird feelings from the driveline. Only comes on once and never comes on again until you use 4wd next. This isn't too big of an issue for me as I will rarely be using 4wd. Will be mainly using it for Surf Fishing in the Summer on the beach. Just seeing if anyone has had an issue similar to me and has found a solution.

Any help is greatly appreciated! This stuff has been bothering me for a while now so I figured I would reach out to fellow Yukon/Tahoe owners to try and find some answers. Like I said I'm a newbie so if i posted this in the wrong section, please let me know! Thank in advance!

My window switches were not working reliably so I took then apart, (not too hard) and filed the contacts that were burnt. Nail file works.They work fine now.