Service 4 wheel drive/key fob/seat heater

WMMC

MEMBER
2004 CHEVROLET TAHOE
70,000 MILES

Hello everyone, First post.
2004 Chevrolet 4x4 Tahoe, 70k miles, original owner.
Yesterday I received a message on my dash reading 'service 4 wheel drive'. This message appears every time I start my Tahoe. Also at the same time the light showing that the vehicle is in 2 wheel drive started working intermittently and will not shift to 4 wheel drive when the indicator light is out. I took it to the local Lube Shop and had the transfer case flushed and refilled, but that was not the problem. Today the seat warmer indicator lights stopped working and the seat heater will not work. Also starting today the key fob will lock the doors, but will not unlock the doors. I read that the switch on the dash panel may be the culprit or the transfer case encoder motor position sensor on the transfer case may be bad for the 'Service 4 wheel drive' issue, but why the seat warmer and key fob also going out all within 24 hours?
Thanks for any help!

5 Replies

MADMIKE1735

MECHANIC
951 POSTS

This is just coincidence. As far as the 4x4 goes, changing fluid wont reset the light. On this vehicle, the 2 MAIN causes, are 1- being the dash pushbutton controller, and 2 the most common cause- being the actual encoder motor located on the transfer case. Without an adequate scantool, this cannot be solved online. Nor can the seatwarmer. As far as the fob goes in the key, try replacing the battery. It is a simple watch/hearing aid battery, and is readily availible at cvs, walgreens, etc. The seatwarmer is a whole different animal in it self. Also, what seat? Driver side? On this vehicle, I believe the heated seat button is located on the door correct? It can be as simple as a bad connection, or worse, a broken wire between the button, and the heating element in the seat. Do you have a local garage that is trustworthy? I would have them go for the diag with the 4x4 as its very tough online. As far as the rest, we should beable to walk you through.

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Wednesday, October 30th, 2013 AT 6:09 PM

WMMC

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3 POSTS

@ Madmike1735

So you say the 'Service 4 wheel drive' issue, the key fob issue and the seat warmer(driver side seat/heater button on door) all malfunctioning within a 24 hour period is all a coincidence?

I will replace the battery in the key fob and tackle the seat heater issue at a later date. As far as the 'Service 4 wheel drive' issue. What is the most likely cause, keeping in mind the indicator light on the dash is intermittent and the transfer case will not shift into 4 wheel drive when the indicator light is out.

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Wednesday, October 30th, 2013 AT 6:22 PM

MADMIKE1735

MECHANIC
951 POSTS

Yes, these are all a coincidence. They are not anyway electronically related. Its weird, im as shocked as you are! Ive never seen this before either. As far as the service 4x4 goes, like I said, without proper diagnostic equipment, I cant tell you for sure whats wrong. In my experience, the most common is the encoder motor- located on the transfer case, but I have seen the pushbutton switch go bad. Do you own a DMM? Digital multimeter? If so, I can try to walk you through testing the pushbutton switch, but keep in mind, if the problem is intermittant, diag will be very difficult. Garages have scan tools that can bypass and actuate components. Which makes pinpointing failure easier. Without these tools, its that much harder to pinpoint a problem. Eitherway, I will try my best to help.

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Wednesday, October 30th, 2013 AT 6:29 PM

WMMC

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3 POSTS

Madmike1735

No I don't own a DMM. As long as the vehicle is operable in 2 wheel drive which it is, as I just drove 600 miles from Amarillo to my home in Houston, Texas today, I think I'll let it go for awhile. If I need help later how do I contact you again? Do I reply to this question?
Thanks for your help.

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Wednesday, October 30th, 2013 AT 6:39 PM

MADMIKE1735

MECHANIC
951 POSTS

Well in TX you shouldnt need 4x4, haha. Im in Connecticut, and getting ready for snow season. Anyways, if you ever need to get ahold of me personally, you can always contact me here- send me a private message, or email me, madmike1735@yahoo. Com I will walk you through diag when you are ready, and have access to a DMM. (You can pick a cheap one up for around 40-60$) you donated, and it is my duty to make sure you get this problem solved.