96 SLS dash flickering until headlights are turned on
 

I just purchased a 96 SLS. The dash flickers until I turn on the headlights or turn on the interior lights - seller said it needed a headlight switch assbly. - which I purchased and did not fix the problem Once the lights are on or the interior lights are on the car acts normally and drives fine - I did notice the DIC on the dash reads my VOLTAGE around 11V never goes above 12v so I had it checked at Advance Auto and they said both the battery and alt are fine??? Before I had it checked I put a meter on the battery before starting and it was at 12.6 V and after starting it was over 13V. Any help??? No wait - PLEASE HELP !!! :)

Paul

well u sound as u may have a bad ground or power loose conection that moves and cause the problem

does all the lights flicker interior ones to
does this problem start when u turn the key on and dont start the vehicle
different things come into play at different stages of the key positions

First - thank you sooo much for your help -

I just went out to try it w/o starting and the tach / speedo / dash lights are flickering w/o startup.

This morning I went out and jacked up the car and got under it and played w/ the alt cables ( big red and small connector ) wiggled everything around and nothing was loose - could not get the little cable off to reseat it but it seemed very tight. Had the wife start it up and BINGO it was good!! Turned the car off and put everything back together / lowered the car and started it and it was bad again - jacked it back up and played around with it some more - it seems now when I start it - it is ok for about 15 seconds or so and then it fails. I did notice that the alt was very hot and I did not have the car running long - I could touch motor / rad hoses ( they were a tad hot ) but the alt was real hot) ??

I again checked for tight and clean connections at the grounds and at the POS cables.. all look good. Placed a DVM on the battery and it read 12.7V - started it up and it was 14.3V but the lights flickering and the DIC still reads only 10V to 11V - I also just noticed today that the Drivers Side Window is intermittently not working but all the other windows work fine??

Quick question - where does the DIC get the voltage reading from???? The little connector or the big red cable?? And what board or module receives these voltages to be displayed??

Just a reminder - if I put on the the headlights the voltage still stays low at the DIC , the flickering stops and the car drives fine.

Again - thanks for any input and suggestions ...
Paul

i recall there is a gm bullentin on the window intermittenly not working after express down
( the fix was replace switch)
well there must be something shifting when u lift the car up to stop the problem
the question is where
do u hear any noise from it bearing noise
ok maybe u could try this
disconnect the cable from the generator and unplug it
turn the key and see what happens
we r just taking the generator out of the loop
also check the ground cable and positive cable at the battery

u may also want to look at your dimmer switch( check it first)

Again, thanks for the help ...

On door window - I will work and worry about the door after the voltage problem-mentioned it thinking it was related to the voltage error.

As for the dimmer switch - ordered a new one and replaced it already and itt made no change.

Heard no noise from the jacked position and it failed regularly from that position. I am about to go out and work some more on the car after I am done typing this and will try to disconnect the connector at the alt and will let you know what happens. Again I can n ot thank you enough for your help.

Paul

OK- I was able to unplug the small connector on the alt
I started the car and it read 10.6V
Turned the car off and reconnected the the plug.

Car displayed over 13V - let car run in jacked position for 5 minutes - 12.8V-13V

Lowered the car and still 12.8-13V - let the car run for another 5 minutes - stayed the same - did go under 13V but was at 12.7V or so

Got in the car and applied foot to brake to take it for a ride - all hell broke loose - trunk flew open, gas door opened, heater came on, lost dash display at times and flickered at other times. When vltage reading was sen on display it was bouncing all over the place from under 8V to 11V

As I stated before - when the flickering occured and I turned the lights on, the flickering stopped and the car was fine - well now turning the lights on does nothing-it still flickering and at times I lose all dash / heater & ac displays??

QUESTIONS - I was under the impression that the small connector sent the signals/readings to the PCM to display on the DIC - if I disconnected the small connectoer how did the DIC display the voltage of 10.6 V??? Where is the DIC / PCM getting the voltage read from?

Could the alt be putting out the correct voltage to charge the battery but the part of the alt that communicates w/ thre PCM is bad - and if so what part and what wire is communicating w/ the PCM.

Of course the seller is not returning my calls - just wanted to get some more info as to help w/ the troubleshooting of this problem. CRAIGSLIST was good to me until this transaction.

Paul

I just unplugged the connector again with the car hot and this time the dash was acting crazy as opposed to this morning when it was cold where the dash was ok and the voltage read 10.6 ..... ????? help !! lol

You have what appears to be some erratic electromagnetic or RFI problems. There is a tech bulletin on this that I can dig back up if needed.
Does the car have a LCD display, or an analog display for the speedo?

i dont like your battery that low to begin with

do u have a meter test the battery it should be arould 12.5 before u start
10.6 is very low

i would almost go and get the battery checked
there is a bulletin on battery and alternator but u seem to have many different things happening so u r not falling into one group or other
try to nail it down so u dont go spend money for good parts

Adam's Apple - could you please be so kind as to look this up - I have an analog dash.

GMTechs - From my first post -

Before I had it checked I put a meter on the battery before starting and it was at 12.6 V and after starting it was over 13V. Any help??? No wait - PLEASE HELP !!! :)

So, the voltage being displayed by the DIC is it wrong - where does the DIC get the voltage from as the positive side of the battery reads over 13V and is connected directly to the alt and the starter - if I were losing voltage at any of those 3 components I would see it a the positive terminal - correct?? And when I disconnect the the small connector at the alt the DIC displays 10.5V ???

So.... I played with it last night and found if I leave the door open everything works - close the door and dash goes crazy. Close the door and it is fine - same I can not drive w/ the door open. Is there a way for me to somehow Open or Jumper Out the door switch to fake out the computer and let it seem like the door is open??

Thanks much for your thoughts and PLEASE continue to give input -

If someone would like to speak to me over the phone on this I would gladly and be willing to call you - if so, send me your number thru email - mine email address is juice13@comcast.net - and I will call ... thanks again.

Paul