Allanr

This subject has been discussed several times and I have read every thread I could find. 1989 S4 with 75K miles. If not driven for 3-4 days battery is drained.
Battery charged and load tested good and is less than 1 year old. Alternator out put tested, 14.4 V and tested good. Problem was traced to fuse #24 where a constant 650 ma drain was found with key out of the ignition switch. If fuse 24 is removed the car will sit for weeks without draining the battery. I have done the following: disconnected all interior lights, ceiling, hatch, door and door jam (red lights). Disconnected the radio and amplifier, the alarm system, tail gate unlocking switches and drive and also pulled electrical connector off the ignition switch. None of these have affected the 650 ma current drain. I have reviewed the wiring diagrams in the 928 workshop manual extensively. Obviously I have missed something. I have fabricated an on/off switch for fuse 24 which I can operate from the drivers position so I can drive the car but this is not a permenant solution. Any suggestions will be appreciated.
Allan Allbritton

Alan

This fuse feeds the interior lights and diagnostic connector. So it must be interior lights or something someone has hung off this...

Have you removed the door end lights as they too come on with the interior lights? 650 mA is about 8W which is a lot... like 2 x 4W door end bulbs...?

Basically looks like your interior lights don't work right - pull the interior light relay XXI if you want to test without this...

Its most likely that the rear hatch tip switch built into the bottom of the hatch receiver is broken and always on - pull the connector off this to test...

Other alternatives for the lights staying on are the relay (as above) the door pin switches or shorting of some of the wires in the interior light fixtures to ground... start with the most likely and/or easiet options (in this case problably the same thing).

Alan

SteveG

I have seen references to a wire on the dome light rubbing or shorting for some reason. Glove box light too. I guess you need to check them all, but I would start with door markers cause they can attract moisture and corrosion, then dome, glove, others.

Alan

Allan - why did you put a switch in rather than just removing the fuse...? what functions do you have on Fuse#24 that you still use/need?

Do your interior lights work otherwise correctly? does your rear hatch release work correctly?

Do you also have an interior light over the fuse/relay panel?

This current amount is too low for a pure short circuit but seems too high for just a relay coil...

Alan

Allanr

The switch was placed on fuse #24 as when the fuse is pulled part of the pod display is inoperative, odometer, also the oil presure and fuel gague is inoperative with fuse 24 out. The current drain has been traced to position 11 on plug E. Fuse 24 supplies current to positions 11, 12, 13 and 23 on plug E in the central electric system. Two wires, red and red/white, exit plug E, position 11, and according to the wiring diagram connect to: interior lights, door contact switches,floor lamps, hatch unlocking switches, diagnostic socket, ABS, alarm system, light timing relay, buzzer contact and ignition switch. As stated earlier, all the interior lights have been disconnected, electrical plug of ignition switch disconnected, relay XXI, hatch release switches, door jam lights disconnected with no effect on the current drain. Thus the request for suggestions.
Allan

Bill Ball

Allanr:

You've actually done very good detective trace it to position 11 on plug E. You've listed all the systems served by the wires exiting there. You disconnected MOST of them to no effect. What about the remainder (ABS, alarm, diag socket)?

Allanr

I have disconnected the alarm system, both the main and aux. module. I do not see how the diagnostic socket could be a current drain as it is just a receptical for a diagnostic tool. I have not pulled the ABS relay but will try that next. Thanks for the suggestions.
Allan

Alan

Here are the all connections on Fuse #26 for an '89:

CE -> Schematic Field - Actual Connections
====================================
XI.1 N/A - Supressor in position XI

E11 -> L66 - Alarm Units (2)
E11 -> K26 - Diagnostic Port (norm NC) + Digi Dashboard
E11 -> D18 - Ignition Switch - "Key-in" Switch supply
E11 -> L5 - (CE:E11->CE:E23) Interior Light Delay Relay (CE:E23->CE:T11) Roof Lights

E12 -> F55 - Mirror Controller Position Switch
E12 -> J5 - Interior Door Lamps + Door end lamps + Door lock tab LED's
E12 -> K28 - Diagnostic Port (Norm NC)

E13 -> M16 - Tailgate Unlocking Switches (L & R)
E13 -> F5 - Glove Box Lamp & Clock

The glovebox lamp is still a candidate ~10W bulb (but is not on E11 as you have mentioned...) the digital dash itself could be faulty and I'd also try removing the Interior Light Delay Relay (XXI) and the Suppressor (XI) since those are both directly connected to this line on the CE panel.

Unlikely but possibles are the door lock tab LED's (only if the alarm is shorted out)... Did anyone attach anything to the tailgate unlocking switch red wires? (should only be to the switch). Does your clock work? does you mirror controller work correctly?

Suggestion: (unless this is what you already did?) - make up some jumpers for the CE panel with a male disonnect one end and female the other end on wires ~ 6" long make up 3 like this...

Pull plug E out of the CE panel and reconnect E11, E12 and E13 only to the panel with the jumpers - check you get the same current readings as before then remove one of the connections in sequence to determine which is drawing the current.

Make sure you always do the current test with the cars doors and hatch closed, (after one door has been opened & closed and without turning the ignition on).

Let us know what you find.

Alan

Allanr

Excellent post Alan. I fashioned jumper wires between the plug and it's receptable on the electical system and this is the way that position E 11 was detected as the drain source. I will revisit the light delay relay XXI and the other items listed in your post served by E 11. Many thanks.
Allan

WallyP

What if the "key-in" switch thinks that the key is always in?

Alan

Wally,
He did say he had removed the ignition switch connections (I assumed for this reason). However I guess the interesting question here is - Allan does your chime work when the key is in and the doors are open?

If not maybe someone disconnected it because it was always on - in that case the driver for it is still on... this would suggest the Key-in switch is shorted closed - you could also just test that switch directly...

Alan

Allanr

Many thanks to Steve G, Wally P, Alan andotherswho provided very hepful suggestions. The problem was traced to an intermittent sticking relay. It was found using the following method. It was known thatthe currend drain was from fuse #24 through connector E position 11. A vom meter was attached to the battery ground strap and to car ground point so voltage drain could be constantly monitered. Doors were closed (windows open) as was the hatch. Current drain was monitered in each of the following steps. Key inserted in ignition and removed, key inserted and turned so digital dashboard illuminated and then removed. It should be noted (door not opened) that greater than 800 ma drain noted and continued for three minutes after key was removed. Door opened and closed, current drain of 300 ma noted and stopped in approximately one minute. Fortunately this step was repeated several times and it was noted that the time for current drain to cease, one minute, sometimes longer. This was suspected as a problem and confirmed when the door was opened, closed and the current drain remained after one hour. The interior light delay relay was pulled and extingused the drain. The problem was difficlt to diagnose due to the intermittent nature. As a rule of thumb to trouble shoot this type of problem, after hooking up the vom, with hatch and doors closed the car must sit for at least five minutes befor any readings are attempted due to the number of delays in the electrical curcits. In addition, a contributing factor is that this car is driven only 2-3 times weekly, short trips with A/C always on. The battery was retested and passed a sever load test. Resting battery voltage was 12.5 v, car at idle and 2,000 rpm 13.5 v. Voltage with A/C and lights on was 13.2. This was precieved as a possible problem, however after a 10 hr charge with a 6 amp charger battery voltage was 13.5 v (some surface charge) and voltage at idle was 14.2 v. Proves you can not test an alternator with out a fully charged battery.
Allan

Allanr

Alan, where did you find the information you posted relative to the current distribution from the respective plugs. Ihave not found this in the factory manuals.
CE Schematic Field Actual Connections
====================================
XI.1 N/A Supressor in position XI

E11 -> L66 Alarm Units (2)
E11 -> K26 Diagnostic Port (norm NC) + Digi Dashboard
E11 -> D18 Ignition Switch - "Key-in" Switch supply
E11 -> L5 (CE:E11->CE:E23) Interior Light Delay Relay (CE:E23->CE:T11) Roof Lights

E12 -> F55 Mirror Controller Position Switch
E12 -> J5 Interior Door Lamps + Door end lamps + Door lock tab LED's
E12 -> K28 Diagnostic Port (Norm NC)

E13 -> M16 Tailgate Unlocking Switches (L & R)
E13 -> F5 Glove Box Lamp & Clock

Alan

Allen - it is all in the factory manuals schematics although rather cryptically admittedly - when you figure out how the schematics work its actually quite easy (plus I've done this a few times...)

Glad to help... this forum has saved me countless hours and dollars - just giving back what I can...


Alan

Allanr

Alan
I have followed the schematics until I almost went blind. I thought that you had found it in the format that you had in your post. Wistfull thinking I guess. Again, thanks for your help.
Allan