1999 LT weird problems

Since I bought this vehicle in 10/04 I have noticed several strange things. In order of strangeness, here they are:

1. While driving down very wet highways, the power door locks closed. I thought it was weird so I opened them. A few seconds later they locked on their own again. Then they kept trying to close even though they already were. I could hear some clicking noise under the dash by the pedals, maybe from a relay. Then they quit working altogether. I couldn't even open them. BTW, pulling the handle doesn't open a locked door from inside.

2. My 4x4 system has auto 4-wheel. Again with wet roads (snow, ice, water) I put the truck in auto 4-wheel and it ran ok for a little while and then the service 4x4 light came on. After I parked the truck and shut it off, I hopped in and started it up again. It was like it had a mind of its own as it was in 4x4 low range. I had no idea how it got there and pushing the button to 2-hi didn't change it. So I shut the drove the truck a little ways and turned it off and on a few times until pushing the button worked and it went back to 2-hi.

3. The driver's side seat heater only heats my left cheek, but it gets it very very hot when on the low setting. The high setting is worse. The other seat works great and has a low and high heat setting that is just right. Now the driver's side seat doesn't work at all. I assume it has blown a fuse, but the passenger side still works. Maybe they are on different circuits.

4. I have two remote entry do-hicky's for key chains. I put new batteries in both and they worked great, for a day. Then one of them quit working. I checked the battery and it was dead, in one day. The other one went from working at 30-feet to only about 10-feet, but it has stayed working now for about 2-months. I've never bothered putting a battery in the bad one cause I think it will just kill the battery again in a day.

If anybody has any advice on how to fix these items, I would love it. I am a DIY most of the time. Thanks

Hi,
for 1) and 2) you can do some wire tracing, but you probably will need the dealer as they have the Tech II handheld computer (cost $3,000) and you need it for diagnostics.
3) My guess is that the heater element developed a hot spot and eventually burned out.
4) Try one more battery, in case you had a bad one.
Take care, Eggert :bananasmi

I can't let this thread die as the problems with my Yukon persist.

My Yukon has been sitting for three days. I went to start it this afternoon and the battery was completely dead. I checked and the interior dome light wheel was clicked all the way up. So I put a battery charger on it, 12V 15A standard charge. Not knowing how dead it was I decided to hop in it and put the key in it. As soon as I turned the key to ACC all kinds of crazy things started happening:
1. Loud constant high pitch noise coming from control box behind parking brake.
2. Tachometer started reading about 3000.
3. Speedometer flipped over to 80 mph.
4. 4x4 switch went to 4-LO.
5. Door locks started locking and continuing trying to lock.
6. Clicking noise below dash by steering wheel.
7. And get this - the odometer 1/10 mile started turning and chocking up miles. It turned about 1/2 mile.

I immediately turned the switch to LOCK and took the key out. I tried it again several times and everything happened again and again and again.

This seems way screwed up to me, like the PCM and everything else computer on the thing is screwed. For the hell of it. I tried starting it. The starter wouldn't kick in but everything I mentioned above continued.

My question is, can the dead battery cause all of this? Can anybody say they've had a similar experience? I am slow charging the battery now, but I am scared of this truck.

take it to a dealer. or else your gonna spend too much time and/or money trying to fix this. for the doors check if the child safety locks are on, these are on the back edge of the rear doors. as for the other problems i'd guess a module somewhere is fried.

Interestingly, after I charged the battery back up for about five hours I went back and tried the key in it. Everything worked normal. It was as if the low voltage and amps from the dead battery with the charger on it weren't enough for the electronics of the truck to operate properly. It really made me worry and I still don't like what happened but it appears that it was caused by the low power supply to the truck. Sometimes, I really like my dodge truck.

I know what the problem is! I have a 99' Denali and had the same problem with mine! It took me awhile to figure it out (months)! Inside your center console is a unit called a Body Control Module(BCM). And the sensor for your keyless entry is in there two. These modules control your stock security system and power door locks. I sank mine in water one day and my truck went CRAZY! After replacing those items, no problems! But the bcm is like $375 new- dealer item only. Try to find someone who knows how to PROPERLY test the modules in the center console! Good Luck! Let me know if that is the problem!

Hi,
I agree with big timer, the problem now is that things work again.
May be there is something stored in the DTC history.
You still need the dealer, their tech II scan tool and probably $200 to $500. There is no way around it.
Tell the dealer all you said in here.
You said that it happend under very wet conditions, so my guess is that some connector (and there are many) may have gotten moisture that eventually evaporated.
That drove the BCM and other electronics nuts.
A visual inspection is in order. This will not fix itself.
You need somebody to pinpoint all malfunctions to some common source.

How did your bun warmer end up?
Take care, Eggert :bananasmi

Do us a favor and keep us updated.

Sounds like the car Christine! Anybody here old ewnough to remember her?

Since our weather has dried up (and warmed up) I haven't had any problems with the locks unexplainably actuating or the 4x4 switch and system. Hence, I have chosen not to replace anything for now. I'll get back on this when I do.