[mickeyb37]

My 1996 ( 73.5k miles) RR is mainly a winter drive for me, so I usually drive it once or twice a week this time of year. I had worked out reattaching fabric that had worked it's way loose from the back of the roof this last weekend. This evening I went out to take the car to the store for a quick trip and the battery was dead. Thinking I had left a door ajar or something stupid like that I jumped the battery and drove it around for a while to charge the battery. I then came home, it was now dark, and turned the car off. Turned the car back on and it started with no problem.

Then I turned the car back off and noticed the dashboard lights did not go out. Didn't matter if I got out of the car or not. Entry lights went off on schedule. Dashboard lights did not. Finally after starting and restarting and checking whatever I could I simply disconnected the battery.

Anyone seen this one before? Electrical gremlin? Thanks in advance.

Mike

Northville, Michigan

 

[Rick-the-Pick]

Becm failure.

You need to change your becm.

 

[wrldky]

Probably the BeCM but I would bet that if you left it off the battery for a while the problem fixed itself and if you are lucky you may not see it again.

 

[mickeyb37]

I continue to be amazed and confused by the electronics and electrical gremlins in this car. After disconnecting the battery since the dashboards lights wouldn't go out and calling a few independent repair facilities I decided I was going to have to bite the bullet and probably rebuild the BECM. I had scheduled a diagnostic appt. at a local repair place recommended from this site. The next day I decided to take the car up to the store just to keep the battery charged and engine working. I reconnected the battery, drove it for about 20 minutes, turned it off, and everything was normal. Dashboard lights were off, everything was perfect. I've left the batter connected now almost a week, have driven it for short trips each night, and it always shuts off normal.

So my conclusion with this car is, disconnect whatever isn't working. Come back in two or three days, reconnect it and it will fix itself.

I realize BTW that I probably do have some gremlins left in the BECM which are causing this irregular behavior. However, I'll wait until it doesn't fix itself before investing $1000 - $3000 in a 14 year old car.

Thanks.

 

[wrldky]

Mike,

Isn't that what I said to do?

 

[Dan_UK_1984]

Do you leave the Climate Control in Auto mode?

It de-humidifies the air and generally a P38 that doesn’t have it on will develop electrical faults - but the headlining will fall off first!! All because the owner doesn’t want to lose 0.5mpg on a car that already only does 16!

The switches on the dash are all soft switches, they use micro switches to send a request signal to the BECM rather than actually completing an electrical circuit as per cheaper cars. The BECM itself although complicated is actually very robust, with all wiring to it double wired for redundancy. But circuit boards and Mofsets do not like being damp. It gets warm and cools down so it is a moisture magnet!

 

[mickeyb37]

Dan , interesting you say that. My A/C isn't working but this is actually my winter car so I didn't worry about it. I only drive it occasionally during the summer and usually at night. The headliner is failing and I just spent an afternoon reattaching it via spray adhesives and a lot of tugging and tucking. I guess I'll have to bite the bullet and get the A/C fixed. Local repair shop said a leak somewhere which could include the compressor which would mean a new compressor. Since I don't drive it during the summer I declined. May have to re think that one. Thanks for the assistance.

Mike

 

[Dan_UK_1984]

I had a leak in the evaporator in my P38 just at the end of summer, within 3 months the headlining was sagging and odd things were happening electrically and the were taking ages to clear. A/C fixed no misty windows, no more sagging and all gremlins went away.

It's so simple really, it's climate control, not Air Con. It's designed to be run constantly.

Take it to an a/c specialist, get them to do a leak test with die and a sniffer, more than likely its the a/c rad at the front.