2002 ford windstar electrical nightmare

Last week the battery was dead, I put a full charge on it and had the battery tested by 2 shops. And then I began looking for a parasidic drain. I narrowed my search to the REM. At this point I reconnected my battery and noted that neither of the power sliding doors work, the rear drivers brake lamp and running lamp do not work and the passenger rear turn signal do not work. All the bulbs are good. I tested continuity from the sockets back to the REM, all is good. I replaced the REM with one from the junkyard, same exact symptoms. Any ideas on how to proceed?

Thanks in advance!
Steve

I don't have guidance for your specific problem, but general electrical troubleshooting is most easily accomplish by using the "divide and conquer" approach.

First check the obvious things, like a blown fuse, or bad light bulbs. Also recognize that when several devices fail at the same time there is usually a single cause for the system to fail. Check the places that all the components depend upon (such as a fuse).

Use your meter to check for the voltage that power all those circuits, and find the place where it is lost.

It never hurts to check the obvious things (e.g. check the battery voltage, or the voltages on the REM).

If available, buy the paper electrical diagram book for your specific model. "Books4Cars".

I don't know if you resolved your problem or not. I went through the same ordeal recently, with phantom drains, dead batteries or fully charged batteries that seemed to drain in minutes. One "professional" shop indicated it was my REM and that started me down a very disappointing path of looking for wiring harness shorts, REM and FEM failures, drains through various fuses and relays.

A second "professional" shop did not fix the problem either.

I spent several weeks chasing drains that were nothing more than the computer being active. It can fool you as you may see up to an amp of drain when the computer is active.

To make a long story short, the problem turned out to be my starter motor. Even though it would start the car OK, I might only get one chance to crank the car after fully charging the battery (usually with the battery disconnected from everything else because of the supposed drains). Even after the car started, and driving up to 50 miles, the car might be dead immediately after turning the ignition off, or be dead within 30 minutes.

I think there was some sort of KO/EO short back through the starter motor. Once I replaced it, the problems stopped immediately.

By "tested", did the shops validate that you had at least 12.6 volts from the battery? How old is it?

Just a couple of months or so ago the wipers on our 2002 were working intermittently. They were also kind of sluggish. Once the started, they'd run, but sometimes they wouldn't respond at all. Once the wife complained, that meant it was urgent. (Plus it's dangerous not to have wipers that work!)

The battery was 3 years old and tested at 12.4 volts. I had the free test at advance auto done and it said battery was OK. I was considering changing the wiper motor but decided MAYBE it was the battery. Given the cold winter coming in Chicago, just to be safe I put in a brand new battery and immediately the wipers began working perfectly. Also the power sliding windows run a lot more smoothly and faster than they have been before. I really thought 12.4 volts was acceptable but apparently that reading isn't the only factor. Maybe the distilled water was low.. who knows? All I know is something was wrong with the battery.

That may not be relevant in this case but a bad battery or voltage regulator (built into the alternator on Windstars) can wreak havoc in bizarre ways. The advice regarding the starter above could be your issue too. If you've replaced your starter with an aftermarket one before, make sure the leads aren't touching slightly somewhere, too. The connector that "wraps around" (for lack of a better way of describing it... it has the 90-degree bend on the end) was making a tiny bit of contact to the other on my Remy-branded replacement causing issues until I bent it back out of the way.