98 GC BCM issue??

[breeaad]

I have a 1998 Grand Cherokee Limited that is having several weird issues I am hoping are related.
#1: When you start it, the blower motor won't blow immediately. You have to adjust the blower setting and it will start, or wait several minutes and it will start on its own. It does have ATC, but it has never acted like this.
#2: Now the temperature setting does a similar thing. It blows hot when you start it, no matter the setting. But if you turn the setting to hot, then back to cold, the blend door will move some to get a cool air. I have taken the blend door motor off, and the door is free and seems to be working correctly. But the motor only rotates the output shaft 1/4 turn. Is that correct? I have crimped a heater hose with some flat-jaws vice grips for the summer, and air is cold.
#3:The battery mysteriously goes dead. Sometimes over night. Sometimes in the matter of hours. Once I have caught a relay in the passenger kick-panel cycling endlessly. But it stopped before I could find out which one. Hasn't done it since. I have also caught the message center and overhead console LED readouts stuck on, even with the key off and out of the ignition. Pulling the fuse did the trick. Fuse is back in and hasn't done it since.
#4: Message center always displays "Rear light failure", even though there isn't one. I assumed in the past this was a bad light outage monitor, and never fixed.
#5: Message center will sometimes display "coolant sensor bad".
#6: Keyless entry works great on some days, not so much on others.
#7: When headlights are set on auto, sometimes they flash on and off. Other times they work great.

With all this being said, I may have numerous issues on a car with 230k miles on it and too many electronics. But could many of these issues be related to a bad body control module? Can I swap it with another vehicle, or does the VIN need to be flashed? What year/options will a donor vehicle need? Does it have to have ATC? Any information would be great.

[breeaad]

Bump!!!

[dornier34]

check the charging system , make sure the battery is good two things can be battery not giving good power , or the body control module is not working properly , check the battery of the key less too let me know . good luck dornier34

[reekor]

1 & 2) Do you have the heater settings set to Auto? If you do it's normal for a delay until the engine worms up.

3) Could be a bad ignition switch.

4) Most of the time that I see this problem one of the 3 bulbs in the 3rd brake light are burnt out.

5 & 7) http://www.automotiveforums.com/vbul...d.php?t=918510

http://www.automotiveforums.com/vbul...d.php?t=950793

6) Did you try fresh batteries?

[fredjacksonsan]

+1 on the "Auto" setting, it's made to not blow until it reaches a certain temperature.

Dornier34's correct also; electrical oddities like this can be caused by a bad charging system, bad battery, or even corrosion in the battery cables (which reduces voltage). I've personally seen corrosion INside the insulation, as far as 8" away from the battery. So I'd suggest that you check your cables well, and have your battery and alternator tested....post back with what you find --

[breeaad]

Originally Posted by reekor

1 & 2) Do you have the heater settings set to Auto? If you do it's normal for a delay until the engine worms up.

3) Could be a bad ignition switch.

4) Most of the time that I see this problem one of the 3 bulbs in the 3rd brake light are burnt out.

5 & 7) http://www.automotiveforums.com/vbul...d.php?t=918510

http://www.automotiveforums.com/vbul...d.php?t=950793

6) Did you try fresh batteries?

1&2) I have tried it on each setting. It does it on all setting, not just auto or heat. Also, it always had a slight delay, but it is different now. The system will only blow hot now. The blend door is not working properly. I disconnected the door motor and moved the door manually. It is functioning correctly physically. But when I operate the motor disconnected, watching the drive shaft, it only rotates a 1/4 turn at most. But I checked another available GC, and it did the same. So I am not sure what the issue is.
3) I have spent quite a bit of time on this one with no solution. But internet research showed this is a common issue and I could not find a solution. Here is the issue: I have a 190mA draw at all times, which is four times higher than it should be. I can pull the #7 fuse in the JB and kill the draw. This fuse powers the BCM. I can unplug the white connecter from the BCM and kill the draw. I have taken the dash apart and unplugged everything, all relays, connectors, etc. Cannot find the cause. Unless someone has a good solution, I will be pulling the door panels soon to check the door modules.
4)All rear lights are working, including the 3 lights in the upper light. I am sure all lights are working properly. I removed the hatch cover and checked all connections, with no solution.
5&7) I will try the solder trick. Thanks!!!
6) I also need to try the fresh batterys in the fob.

Here is my next important question: Can you swap a BCM from another GC without flashing the VIN??

[breeaad]

Originally Posted by fredjacksonsan

+1 on the "Auto" setting, it's made to not blow until it reaches a certain temperature.

Dornier34's correct also; electrical oddities like this can be caused by a bad charging system, bad battery, or even corrosion in the battery cables (which reduces voltage). I've personally seen corrosion INside the insulation, as far as 8" away from the battery. So I'd suggest that you check your cables well, and have your battery and alternator tested....post back with what you find --

Thanks for the feedback. I have been through the connections closely, and have had the battery checks twice by two different machines. The positive cable to the starter has a dark spot in the insulation a few inches from the battery terminal, like it got hot at some point. But i checked the voltage drop across this part of the cable and it looks OK. I would like to replace the cable just to be sure, but I hate to hack up the original batter terminal. But as this cable goes to the starter and not the alternator, it stands to reason its not causing a battery charging issue.