REM 2003

[Tommy B]

Background: A couple of years ago the rear park assist became intermittent, then quit entirely. Between then and now, other interior switches (door locks , windows) on doors other than driver door stopped working. 3 mos ago trans interlock wouldn't release and brake lights didn't work, with key on. Engine cranked but wouldn't start. Disconnected batt, interlock released ,put car in neutral, reconnected batt and car started. Figured the brake switch went bad, replaced it and car ran- for a couple of months. Last month same thing happened, replaced the switch again, no good. Now none of the rear lights or turn signals worked, trunk release didn't work, and car in neutral would crank but not start. Checked in this forum and found list of things controlled by REM (thanks Joegr), matched almost exactly all the things that weren't working. Got a matching part # REM from junkyard and plugged it in. For $50, worth a shot. What do you know, it worked great, interlock good, car starts, all lights and turns good, even the rear park assist started working. Well, the park assist worked for a day but then stopped. Door and lock switches and trunk release still don't work.

The question- does the REM need to be programmed, and if so, is there a good chance that the failed switches would work again? Seems unlikely that that many individual switches, relays etc. would go bad. A common problem like REM seems more likely. Any ideas?

Thanks for any insight you can offer.

-Tom

 

[joegr]

It should not need to be programmed. Check the connector(s) and wiring to the REM.

 

[Tommy B]

Thanks, Joe. Maybe the inop systems all route through 1 connector, I'll check the wiring diagram. That would be easy enough.

 

[joegr]

You can start by just unplugging the REM and plugging it back in. If you get some functions back, even if only for a short while, it points to the that connection or the wiring near it.

 

[Tommy B]

Will do, thanks. Forgot the rule: start with simple and go from there. Bought a can of electronic cleaner, while in there I'll spray all the contacts (batt disconnected and plenty of dry time, of course). Will advise of results.

 

[Tommy B]

Pulled REM, cleaned all male and female connections to the extent possible. No luck. Car starts and runs fine, but certain accessory systems that I understand run through the REM still don't work. Here's a list of what now works and did not prior to REM replacement, or did so intermittently:

All rear lights inc. brakes, turns, backup
Trans shift lever (interlock properly disengages when key in ignition)
Fuel gauge
Battery holding charge (would discharge if not disconnected)

Here's what's not working:
Rear park assist
Power door locks on all doors other than driver's (driver switch will operate only driver door lock, no others)
Power windows on all doors other than driver's (driver switch will operate all windows)
Dash trunk release button

I learned that the used REM I installed came off a 3.0, not a 3.9, but i don't see how that would make a difference given that it's likely the controlled systems are the same in both. Is it possible the REM needs to be programmed?

With respect to the rear park assist, the one time I let my GF borrow my LS she managed to get tapped from behind at a light. The system seemed fine at the time, but stopped working a couple of mos. later. Could be a bad connection there, going to pull the bumper when it gets warmer.

Also, there's a roof leak, probably coming in through the sunroof. The water drains down the pass side A pillar and collects in the door pocket. Perhaps part of the problem? Thanks, all, for any insights.

 

[joegr]

...Also, there's a roof leak, probably coming in through the sunroof. The water drains down the pass side A pillar and collects in the door pocket. Perhaps part of the problem? Thanks, all, for any insights.

Well, that one's a known issue. At each of the four corners of the sunroof, there is a drain hose. The hoses shrink and disconnect. Some have been able to stretch the hose back and put a clamp on it to keep it connected. Others (like me) have had to splice in a short extra piece of hose. Much like the cooling system, you might as well do something about the other three hoses while you are in there, because eventually they'll pull out too (well, at least the front ones will). Anyway, you'll have to partially drop the headliner to take care of it.

Theoretically, the REM needs to come from an LS with matching equipment or to be reprogrammed, but I can't promise that this is your current problem.
Failure of the rear park assist as it ages is not too uncommon. There is a radar module hidden under the bumper cover in the center that might be subject to impact damage. That said, mine has failed (not due to impact, just due to time I guess), but the ultrasonic sensors still work and I still get short range warnings.

 

[04_Sport_LS]

I thought twice and 3 times about bringing this back up,,, but there have been other people on this forum... that suspect certain problems with the electronics in the LS are cause by "grounding issues". The idea is,,, that because the subframe/chassis is spot welded together... (and the battery is in the trunk)... that over time due to corrosion,,, a lack of "grounding" can cause an issue with the electronics in the LS.

There was a thread sometime back... where a poster "supposedly" fixed his issues... by running extra wires in a "star ground" type wiring. Star grounding has been used in other electrical sytems for years. The idea is to take ALL grounding points... to a central point. Thus the term "star" ground. It gives all related electrical components... a "common ground"... supposedly eliminating any differntial in resistance and voltage,,, allowing the electrical system to function properly.

Just something to consider. Tommy... your issue COULD be corrosion in connectors on the LS. But if you can't get the problem solved through normal diagnotic proceedures,,, you might want to start checking all of your grounding point for resistance.

I said it for what it's worth. (which might not be much).

 

[Tommy B]

Appreciate the responses. I'll pull the headliner and the bumper when it warms up a bit and address those issues (leak and rear [park assist).

I called the dealer to see about a possible reprogram of the REM. In what may be a couple of firsts, at least in my experience, the service writer admitted he didn't know whether it was required and that he would call me back after speaking with the tech. He called back in about 10 minutes and informed me that the tech said that if the switches at issue did not work as the result of a REM issue then I'd get an error light on the dash. So long as the car's otherwise working a reprogram would not be necessary, and "I don't want you to have to waste your money on something you don't need"(!). I'll take the tech at face value and look elsewhere for the switch issues. The grounding suggestion is interesting. Another LS puzzle to be pieced together. But refreshing to speak to a service writer who (a) says he doesn't know, (b) finds the answer from someone who does know, (c) calls back quickly to provide that answer to a non-paying customer, and (d) doesn't want to waste my money.

I wonder how long he'll last in that job

 

[Tommy B]

One other question on the REM- while the part # of the used REM I installed (3W4T-13B520-AD) is identical to the bad one I replaced it with, there's another designator I didn't pay much attention to- REM-FK. Anyone know what that indicates and would it make any difference if that indicator on the replacement was REM-FL? Thanks once again.

 

[joegr]

No idea on the FK/FL.
This may help with which wire does what. I don't know how to keep the site from shrinking it.

 

[Tommy B]

Thanks (again) for the info, Joe. I don't believe the designator would make a difference so long as the part #'s the same, but you never know. About all I can tell is that "L" is the letter following "K" in the English alphabet so perhaps it indicates the next assembly run of the device. Who knows.

 

[larnold1]

Thanks (again) for the info, Joe. I don't believe the designator would make a difference so long as the part #'s the same, but you never know. About all I can tell is that "L" is the letter following "K" in the English alphabet so perhaps it indicates the next assembly run of the device. Who knows.

Hey Tommy, i know this is an old thread now but you seem to have had similar problem to what i am currently experiencing. My car cranks but will take about 10-15mins sometimes before she will start. Check engine light that says its a problem with my REM is on in my 03 lincoln ls. Did you end up reprogramming another REM or what was the end solution that solved your problems?

Thanks in advance!

 

[Tommy B]

Problems not solved! Never tried the reprogramming, I have a few other vehicles to drive and got sidetracked with other things and work so the LS was put on hold for the most part. The car moves forward when I put it in gear and performs all the necessary mechanical functions to get me from point A to B in a spirited manner if I choose, and when I do drive the car it's usually only me so I don't care all that much about passenger door locks and windows, etc. I like the LS, however, so I keep it around to "entertain" me when I feel like playing with it. Maybe when I retire I'll take the time to address it once and for all. Wish I had a better answer for you! Good luck with your issue.