Please help with electrical issue...battery drain from inside lights circuit
#1
Please help with electrical issue...battery drain from inside lights circuit
Hi
Recently purchased a 94 Targa that has a battery drain problem. The car is pulling about 790 mA from the battery with everything turned off. When I remove fuse no. 11 (inside lights) the draw is reduced to about 100 mA...still not quite what is reported here as normal but much improved and obviously most of my problem.
Trouble is I cannot locate anything on the circuit that corrects the problem. The interior light and glove box light have been removed and still my VOM shows 790 mA. Even removed the clock and the adjacent dash gauge, as it is tiptronic and I know somehow the tiptronic gear display is on that fuse, still no improvement.
Please offer any suggestions....maybe someone here can read the wiring diagram and can tell me other items on this fuse? I cannot seem to make much from the diagram.
The car had a Kenwood radio and a power amp added previously...Initally thought the problem was the amp, I removed the amp and still have an issue...I suppose something could have been added to the circuit somewhere??? Any suggestions?
Thanks
Gary
Recently purchased a 94 Targa that has a battery drain problem. The car is pulling about 790 mA from the battery with everything turned off. When I remove fuse no. 11 (inside lights) the draw is reduced to about 100 mA...still not quite what is reported here as normal but much improved and obviously most of my problem.
Trouble is I cannot locate anything on the circuit that corrects the problem. The interior light and glove box light have been removed and still my VOM shows 790 mA. Even removed the clock and the adjacent dash gauge, as it is tiptronic and I know somehow the tiptronic gear display is on that fuse, still no improvement.
Please offer any suggestions....maybe someone here can read the wiring diagram and can tell me other items on this fuse? I cannot seem to make much from the diagram.
The car had a Kenwood radio and a power amp added previously...Initally thought the problem was the amp, I removed the amp and still have an issue...I suppose something could have been added to the circuit somewhere??? Any suggestions?
Thanks
Gary
#2
Rennlist Member
Join Date: Jun 2010
Location: Detroit (Rock City); 1990 C4
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IIRC the interior lighting circuit is strange- possibly the engine department, trunk, and glove department lamps are all energized together? I had a similar issue and found that the glove box lamp switch had failed and was keeping things energized.
#4
Three Wheelin'
Yep, engine lid and trunk lid lights are all on the same circuit as interior lights. Go round and depress all the plunger switches to ensure the respective lights go out.
I just fixed a similar intermittent issue caused by the trunk light. On occations it wasn't going out despite the plunger switch being depressed. Popped out the light unit and switch to inspect the cable as it must be shorting the switch somewhere. Sure enough, just an inch along the switched earth cable where it connects to the light unit was a fine cut in the insulation. Reached my fingers into the bonnet hole to find what could of done it and there is a sharpish metal edge thats forms part of the strengthening for the bonnet hinge mount. Taped up the wire and bent the light unit terminals 45degrees from straight to stay well clear. Problem sorted.
I just fixed a similar intermittent issue caused by the trunk light. On occations it wasn't going out despite the plunger switch being depressed. Popped out the light unit and switch to inspect the cable as it must be shorting the switch somewhere. Sure enough, just an inch along the switched earth cable where it connects to the light unit was a fine cut in the insulation. Reached my fingers into the bonnet hole to find what could of done it and there is a sharpish metal edge thats forms part of the strengthening for the bonnet hinge mount. Taped up the wire and bent the light unit terminals 45degrees from straight to stay well clear. Problem sorted.
#5
Thanks. I will check those items this evening, I know it has no bulbs in the external socket so a PO made some attempt. I will isolate the switches, etc to make sure.
My power windows do not work at all with the ignition off.
Thanks
Gary
My power windows do not work at all with the ignition off.
Thanks
Gary
#6
Rennlist Member
+1 for the trunk light classic issue. There is a connector on the lead not far from the light, just disconnect it and see if the issue goes away. The other issue is the radio alarm lead on the radio sleeve. it has been known to cause a drain if a different radio is installed and it is bent out of the way or cut.
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#9
Progress
OK...
I will double check my work but it looks like I have not one but two bad switches...neither the front lid nor the rear engine lid turn off the circuit when closed. Does anyone here know exactly how this circuit is wired, do I have two bad switches or is a ground missing somewhere?
I will double check my work but it looks like I have not one but two bad switches...neither the front lid nor the rear engine lid turn off the circuit when closed. Does anyone here know exactly how this circuit is wired, do I have two bad switches or is a ground missing somewhere?
#10
Three Wheelin'
I believe that those switches have one +12v wire and they ground through their mounting screw. When the spring/plunger is pressed in, the connection to ground is broken. Sounds like something in the mechanism is bent so that they are shorting to ground.
The 100mA draw is from the alarm- it pulls that for ~5 minutes after door/trunk/funk is shut. I think that the interior light timer goes through the alarm brain. Scratched my head for a while to track that one down!
The 100mA draw is from the alarm- it pulls that for ~5 minutes after door/trunk/funk is shut. I think that the interior light timer goes through the alarm brain. Scratched my head for a while to track that one down!