electrical gremlins, the whole family...

b_pappy · 02-05-2012, 01:33 PM

Wow, so many problems, but I suspect they are all related.
The saga began with a dead battery, so I put in an Optima red top and put it on the tender. Fresh battery seemed to run & start, still throwing codes on the DIC, I assumed from low voltage.
So last Friday I'm going to drive car, so Thursday night I unplug it from the tender. Friday morning it's dead. Zip. Nothing, won't even let me in the car.
So now I put it on the real battery charger for a day. Looks better, lets me in. Starts up, the gauges do their sweep, settle in, then oil pressure drops and the car stalls. I barely saw it, so I'm not sure which happened first, did it stall and lose oil pressure, or the other way around?
Now I'm out there. back to breaking in through the trunk, 12.75 volts in the battery, on the charger and still nothing. I disconnect teh battery and touch the battery cables to reset the computer. I hook up the battery, the alarm goes off and now my fobs won't stop the alarm.
I put the fob in the glove box and still no green light. I get out, close the door to walk away and the green light comes on, but I'm back to where the fob won't let me in.
Probably a long rambling post, but I'm open to suggestions. We're going to try and scan it with a Tek II a little later.
Bruce

Stella · 02-05-2012, 09:09 PM

Have u checked your fob batt. Could b loosing communication? Check for any corrosion on the batt. cables, sounds weird good luck.

b_pappy · 02-06-2012, 10:38 AM

Well it would not even let the Tech 2 communicate with the computers. No Comm was the error, both fobs, even in the receptacle in the glove box. Two different car batteries, the original and the Red Top.
I'm open to suggestions, and my mechanic is digging deeper into the schematics.
Bruce

b_pappy · 02-07-2012, 08:50 AM

Making progress, pulling fuse 11 & cycling it restored RKE communication, but when running it is still throwing lots of error codes and keeps losing comm to the RKE and suspension module. At least it starts again.
Bruce

Stella · 02-07-2012, 08:34 PM

Could they have a common ground that might be loose. Electrical gremlins ain't no fun GOOD LUCK!

b_pappy · 02-07-2012, 09:43 PM

Still looking. Think I have it narrowed down between the two modules. Could be a ground though, just haven't figured it out yet.
Thanks for the thought.
Bruce

XLRATING · 02-08-2012, 01:05 PM

Definitely felt a big "Ouch" for you when I read the Tech 2 couldn't even communicate - wonder where do you go from there? I don't have any helpful info but I hope you & your mechanic can sort it out.

b_pappy · 02-11-2012, 10:05 AM

Okay, thanks to a great mechanic, a Tech 2 and some research we found the problem.
We got the car talking again, but still had no communication to the Suspension Control Module. We thought we had it isolated, but the top still wasn't working. SCM operates on LAN2 (high speed), the top was secondary, what took them both out, and what was still draining the battery? We went into the trunk where the Suspension module resides and when we opened the panel there was about 4" of standing water in the black recess they are located in.
I'll post some pictures later, but it looks like I need two new modules.
Right now I'm shaking my head; mad at myself, how did so much water get in there? I have to go back and read the threads about the vent tubes clogging.
For the record, the car usually resides in the garage, but when I picked up the '64 Corvette I parked the XLR in the back yard, 90% covered except the trunk area. We then went on vacation and I heard it rained quite a bit while we were gone.
Like I said, pictures coming later. Don't let this happen to you.
Bruce

Crimson Pearl · 02-11-2012, 10:41 AM

Quote:

Originally Posted by b_pappy

For the record, the car usually resides in the garage, but when I picked up the '64 Corvette I parked the XLR in the back yard, 90% covered except the trunk area. We then went on vacation and I heard it rained quite a bit while we were gone.

Looks like you need another garage.

When I bought my XLR, one of my other cars had to go, as I was not going to let any of my vehicles (with the exception of my daily driver) sit out in the weather.

Glad you found the problem!

Cadillac Tech · 02-11-2012, 10:47 AM

Thanks for the information. Sorry to hear about your problems. Let us know how things turn out.

ccclarke · 02-11-2012, 01:20 PM

Water accumulation in the left trunk pocket that houses these two modules is not just expensive, it's entirely preventable and one of the easiest problems to correct. You don't need a mechanic and the tools are really cheap --all you need is a pair of eyes. (Even one will do!)

If you haven't inspected your drain line, it takes all of five minutes to do so. This problem has been posted to death, and even veteran XLR owners aren't immune to it.

It doesn't matter if you normally park indoors; unless you live in Sub-Saharan Africa, water can (and will) accumulate over time, flood the connectors and wipe out these modules if the drain line is plugged.

Put a light under the drain, open the trunk, remove the cover over the compartment well and look down. If you can't see light, clear the obstruction and cut the tip off the plastic drain line (these have a tendancy to crimp themsleves shut over time or clog with road grime.)

Flooded compartment: > than you want to spend.

Peace of mind: Priceless!

CC

b_pappy · 02-11-2012, 02:32 PM

Yeah, I'm kicking myself for not paying more attention, except I thought I was special as I never drive the XLR in the rain. Well, I parked it in the rain in a rush.
The drain was plugged by the back half of a broken off plastic snap.
I'm cleaning connectors, and bought a new Folding Top Module. The Suspension Module appears to be on national back order. I may need help with that.
Bruce

BoughtTheXLR · 02-11-2012, 06:32 PM

Bruce's experience finally got me out to check mine, something I've of course been going to do any day now since I bought it...

My 2008 has no plastic tube, just a very tiny drain hole -- less than a quarter inch. (A piece of 1/8 heatshrink would go in, but barely). It was almost clogged by dust surrounding a small bit of carpet fuzz.

I believe I'm going to make some better arrangements to protect against a future clog. My initial thinking is a somewhat bigger hole in the back, about a half inch up, with a 90 degree plastic hose fitting to minimize water entry from splashes. If the little hole clogs then at least the compartment should not fill to the level of the electronics.

onalaska · 02-11-2012, 06:58 PM

The wiring enters from the top and is long enough that the modules can be relocated above the well and behind the trunk liner eliminating the problem all together. That only leaves the pump in the well. Might be worth considering.

b_pappy · 02-11-2012, 07:32 PM

Yes, this has been discussed before, but it bears repeating.
Just so it is really clear how easy this to check, and how expensive it is to repair I'm posting a few pics.
This area is just inside your trunk, it's that easy to check. I have the carpet pulled back because I have to remove two modules.

This picture vaguely shows a previous high tide. Notice two connectors were completely submerged. The aluminum module is the Suspension control module. Just forward of it is the black plastic Folding Top Module. My really good price on these parts was 378 & 283 respectively. That's if they can locate the Suspension module. Currently it shows national back order.

No leaves, but this broken plastic trim retainer was the culprit, stuck in the drain tube like a stopper. (Shown on schematic for the wiring)

This is the drain tube. Easy to reach, don't have to jack the car, get dirty or anything. Just give it a squeeze to make sure it's clear.

Hope this saves someone else.
Bruce