[junglejustice]

Security / Alarm System Linked Dash Climate Control Unit!? (Trunk Release & Gas Cap?)

So, this one drove us MAD yesterday! (1995 164 LS in overall good condition.)

The good news is that we located some loose connectors behind the climate control that finally solved our remaining stepper motor issues (after pulling half of the bloody car apart), but here's the current issue!

The trunk release button on the climate control / dash unit operates intermittently. The gas cap cover / flap release also works only sporadically. There appears to be some connection with the security system! "APPEARS" being the operative word here... If we disconnect the battery, remove the climate control display unit, reinstall it, rest the alarm key in the trunk to the ON position, reinstall the climate control, reconnect the battery, cycle the door locks with the key fob, then the trunk and gas cap buttons work. For a little while...

What's particularly challenging, is that we can't get consistent results from our testing! Sometimes they work with the alarm system in the OFF position and sometimes they work with it in the ON position. Sometimes they just don't work at all. We are able to energize the trunk release relay (behind the carpet in the trunk on the passenger side of the car), from the connector end and get the trunk release to operate. The gas cap release has an extra wire and it is not clear what to jump where in order to get it to work via the relay. We are able to simply jump it from the power IN to the power OUT connectors, and then the door releases.

The door does work sporadically from the dash button though. Intermittent operation of both trunk and gas door from the buttons on the dash unit, corresponds with the little lights for each respective button working and not working. (I.E - If you push a given button and it lights up, the corresponding release activates; if the little light on the button doesn't light up, the corresponding release does not operate!)

I can shut the car off, go to bed, and the next morning I'll maybe get a single, onetime operation from each and then nothing again after that... Or not...

 

[pinino]

Intermittent electrical gremlins are the worst. Since you are experiencing failure of two relatively unrelated units, but where both units are housed in the trunk area, I wonder if you might have some grounding issues (which might reflect the inconsistencies that you are experiencing). Look over the manual and see if you can establish the "G" points for both circuits (they may be on the same stud). And then loosen the nut, clean the lugs and retighten. Of course the gremlin could be hiding some other place. I know for sure there is a bundle of grounded wires behind the right rear fender liner in the vicinity of the gas cap solenoid, you might start there, but check the manual first!

 

[144]

I think I'd start with checking continuity at the HVAC control unit switches.

 

[pinino]

Is the gas door release in that unit? I was thinking it was elsewhere like in the 1991-93 cars suggesting bad grounds at the target solenoids.

 

[144]

Yea. It's a separate panel. Disregard.

I don't have a 24v wire diagram, but on the 12v, the Trunk and Filler Door share power from the Aux Fuse Box F3 fuse (G2, 30A). When the Filler Door is NOT activated, the relay I53 allows power from F3 to pass though the relay and onto the dedicated Trunk Opener Relay I52. So Aux Fuse Box F3 seems to be the common point where circuits are shared. I think G2 is right above the main box at the driver's left knee. I'd start there and chase to the G170 connector in the right footwell, then to the I52 relay in the right trunk area. That's assuming, of course, that the LS has the same wiring for that circuit.

 

[Alfisto Steve]

Yea. It's a separate panel. Disregard.

I don't have a 24v wire diagram, but on the 12v, the Trunk and Filler Door share power from the Aux Fuse Box F3 fuse (G2, 30A). When the Filler Door is NOT activated, the relay I53 allows power from F3 to pass though the relay and onto the dedicated Trunk Opener Relay I52. So Aux Fuse Box F3 seems to be the common point where circuits are shared. I think G2 is right above the main box at the driver's left knee. I'd start there and chase to the G170 connector in the right footwell, then to the I52 relay in the right trunk area. That's assuming, of course, that the LS has the same wiring for that circuit.

This what I said in your other thread http://www.alfabb.com/bb/forums/5952889-post7.html

 

[Alfisto Steve]

Yea. It's a separate panel. Disregard.

I don't have a 24v wire diagram, but on the 12v, the Trunk and Filler Door share power from the Aux Fuse Box F3 fuse (G2, 30A). When the Filler Door is NOT activated, the relay I53 allows power from F3 to pass though the relay and onto the dedicated Trunk Opener Relay I52. So Aux Fuse Box F3 seems to be the common point where circuits are shared. I think G2 is right above the main box at the driver's left knee. I'd start there and chase to the G170 connector in the right footwell, then to the I52 relay in the right trunk area. That's assuming, of course, that the LS has the same wiring for that circuit.

Yes check 30A fuse in G2 aux fuse box. This what I said in your other thread http://www.alfabb.com/bb/forums/5952889-post7.html

 

[pinino]

JJ, I assumed that you already checked the fuses. Anyway, back the ground; I just checked the electrics schematic, BOTH gas door and trunk lid solenoids use same grounding point—G186—located under right side carpet in trunk behind wheel well.

 

[junglejustice]

Yes, thanks, fuses, relays and grounds - all checked!

The plot thickens...

So, I have now been able to pinpoint the decisive factor in the intermittent nature of this fault! Cabin temperature! I **** you guys not!

So, it's really cold in Seattle right now. Yesterday morning early-early - both gas cap and trunk release buttons work flawlessly - 100% - time after time. I went out there throughout the day - worked every time - car cold...!

Last night I started the car up, let it warm up the cabin nice and toasty, and went for a drive... I came back, stopped the car - NO OPERATION from either button! Tried it over and over - just dead! So, I parked the car, and went to bed pretty well annoyed!

I woke up at 3-4 AM this morning with a clear as daylight thought: "...wonder if it works right now..." So, I went out there in my boxers and sure enough - cold as heck outside - both buttons operate flawlessly - REPEATEDLY!

Went back inside feeling pretty good about it - even cooked a pound of bacon to celebrate my find - but now I had to verify my findings! So, I got ready for the day, went back outside and tried it - car cold - both still worked 100%!

I fired the car up - let it warm up nicely - and drove to work... Got the cabin nice and toasty, arrived at the office, tried it - DEAD! Well I'll be a monkey's uncle!

Talked to the owner again and sure enough, after the gas cap release button's fail, the trunk release was next and now most recently, the hazards / emergency flashers stopped working as well - all buttons on that top row - side by side...!

Anyway, talked to GOATS (Bob Gautier) and must say, that man is SOLID! He's going to fix those buttons for us on this unit as well (he did the screen years ago and the displays still work 100%...)

I'm sending the unit down to him this weekend. There is a known repair for those buttons! I'll report back!

 

[Del]

Yup, Bob's a great guy. Had fun meeting him and his family a couple of years ago near San Diego. The panel in my LS works like a champ after he fixed it.