Central warning lights stay on..

[RobbieStrosek]

Hello all,

I have this rather frustrating thing with my 928 "84 ..

I got it of a guy that needed money to get married hehe.

Now i did alot of things already on the electrics, but now the only thing left is my central warning system lights.

They stay on after the engine runs...
I did already the following things:

replaced the module
replaced the ignition switch
cleaned the 14pin connector
checked if there is 12V on the blue wire comming from the alternator
cleaned grounds
checked kabels

nothing seems to help....funny things is this:
when i turn on the ignition all the lights come on
turning to start, engine starts, lights stay on....
now...when i turn back the key slowly till the engine stops...then quickly turn key back to start position ...the warning lights go out..and the central warning system works fine...breaklights go out after hitting the brakes and so on....

but the engine is not running at this time ....

its killing me mentaly grrrrrrrrr

anyone have any bright ideas ? its the only thing left on this project before it goes to the paint shop....

cheers everyone and thanks for reading up on my problem..

[aluminum]

Could be a lot of things setting off the Light the question is what.
worth a try > Disconnect the battery and turn on something to drain any power like the Ignition Key / parking lights to drain all power in the system. reconnect the battery and try it .
On some cars this well reset the Computer. Are some Electrical Experts that can help you here on this forum I am sure they well chime in after seeing your post . If no go then you need to discover just what is setting off the light . I seem to remember something related in the Left ( Drivers side foot-well behind the carpet Dead Pedal area ) having something to do with the central warning system but may be wrong with that.
This Link Related may help you Check it out:
http://jenniskens.livedsl.nl/Technical/Tips/Files/Porsche_928_CentralWarningSystem_Repair_rev1p0.pdf

[neil30076]

I don't recall from your posts over on rlist - have you removed and/or disconnected the pod? I know from experience that if you reverse the 2nd and 3rd connectors from the right as you look into it on an 81/82 you will get very weird light problems.

[Mrmerlin]

The warning lights staying on after start is usually due to a charging issue

[mproseusa]

Hey Neil, I too have a warning light issue. But mine shows up when I accelerate. The coolant temperature gage shows normal, but the little red light at the top of arc on the gage will flicker and the Warning light comes on. This only happens when accelerating and sometimes when I make a hard right hand turn. Should I reverse the two connectors? Will that affect anything else? Thanks.

[neil30076]

Mike, NO! - do not reverse the 2 connectors, I only suggested this because if you pull the pod and accidently reverse them all the lights do come on, and gauges do weird things.
For your problem....
There are 2 wires on the coolant temp sensor, one goes to the gauge, the other to the central warning unit and then the light. If the light control wire shorts out to ground the light will come on. I would follow both the wires from the coolant sender back up into the main harness, i think you will find your problem.
It could just be hanging off and touching ground also.
For ref 1982 wiring diagram part IX right in the center is the sender, the wire back from the W terminal is the overtemp light trigger.

[mproseusa]

Thanks Neil. I'll check those wires. I'll report back.

[neil30076]

Originally Posted by mproseusa

Thanks Neil. I'll check those wires. I'll report back.

LMK if you need the wiring diagram ...

[mproseusa]

neil30076
I've been doing a little checking of the wires and the wiring diagram. However, it has gotten very uncomfortable here in Conroe, TX. The temps hit 27 F this morning and have warmed up to 30 F. My garage isn't much warmer, so I've put the research on my wires on hold ... 'till it warms up a bit. I really want to fix this problem and I will report back as soon as it thaws out.
Thanks again.

[JK McDonald]

Hey Mproseusa - The wave of cold weather has caught us all by surprise and curtailed just about everyone's maintenance activities. I've a couple of friends down toward Conroe and have taken the route through "Cut and Shoot" many times. Man - I'll be glad when they finally make Hwy 105 into a 4 lane road.

I had an odd master warning light that would come on intermittently when I bought "Lady In Red". It turned out that the previous owner had twisted some poorly insulated brake pad sensor wiring together in the front wheel wells. What made this problem a little difficult to chase down was that the brake pad dash warning light would only FLASH for a instant during a turn. Naturally while making a corner - you'd miss seeing the warning light that triggered the master warning lamp. Just remember that even an intermittent warning light can activate the the master warning circuit.

Good Luck, Michael

[mproseusa]

Thanks Michael, The low this morning was 28F, and not expected to get too much better (it's all the way up to 42F now). My wife and I take 105 through Cut and Shoot on our way to Lake Charles several times a year. There is a bypass for Cleveland now which really cuts the travel time to Lake Charles.
I am going to wait to do any more checking on the wiring until it gets much warmer
I got to thinking about the pod, and when I changed the ignition switch I did have the pod out so maybe I disturbed something on the foil. I need to adjust the speedometer needle anyway so I guess I'll bite that bullet when it gets warmer.