The pictures shows the wiper switch, radio ,cigar lighter etc. is connected to C211 ground. For all I know the EQ could have failed due to ground issue. I am going to connect the EQ to a battery and see if it works. It did cut off once in a great while. Thanks

It looks like C211 goes to the wiper motor. If I'm looking at the diagram right it goes through the firewall, through another grommet, then back through the firewall again. Although it doesn't show anything I would bet there is a ground block on the engine side of the firewall where the harness goes through. Other than that I'm at a loss without actually seeing the car and the rest of the diagrams. If nothing else take a piece of the same size wire and splice in somewhere close to C211 and run it to a grounding point.

 

It looks like C211 goes to the wiper motor. If I'm looking at the diagram right it goes through the firewall, through another grommet, then back through the firewall again. Although it doesn't show anything I would bet there is a ground block on the engine side of the firewall where the harness goes through. Other than that I'm at a loss without actually seeing the car and the rest of the diagrams. If nothing else take a piece of the same size wire and splice in somewhere close to C211 and run it to a grounding point.

Thanks that's a good ideal

 

Here is a diagram of a 2800 I found on the internet.
Hopefully, its the one you are using.
If so, you can use the wires "RED" = +12v, and "BLACK" = Ground for testing. but don't disconnect them from the unit.
The voltage measured across the RED and BLACK wires should be a constant 12v (it should always be 12v, even if the ignition switch is off).

Do you know which type of door trigger you are using?
Does the door trigger change from nothing to +12v when the door is opened? or closed?

View attachment 278117

There are two RED +which one should I use? I'm looking this info over and ready to go test so if you could let me know ASAP . Thanks

 

There are two RED +which one should I use? I'm looking this info over and ready to go test so if you could let me know ASAP . Thanks

The red one connected to the fuse in post#18.
it should always have +12v, even if the ignition key is off.

 

So we're going to play the days and days of exhaustive meter checks and head scratching yielding no results game before finally shotgunning all the grounds out of desperation then? That's understandable; been there, done that. It took me many iterations of this process to arrive at the advice I gave previously. We analytical types want to follow a logical troubleshooting process from the source to the smoking gun, and to understand why the gun was smoking. More often than not, the issue of automotive grounding confounds the analysis and the analyst, and refuses to deliver any satisfaction in the form a smoking gun or even a warm one. You are wasting your time, but I understand too well that the truth of this is something one must learn first hand.

 

There are two RED +which one should I use? I'm looking this info over and ready to go test so if you could let me know ASAP . Thanks

There are two RED +which one should I use? I'm looking this info over and ready to go test so if you could let me know ASAP . Thanks

There are two RED +which one should I use? I'm looking this info over and ready to go test so if you could let me know ASAP . Thanks

The red one connected to the fuse in post#18.
it should always have +12v, even if the ignition key is off.

For the + input trigger I got a 2.5mv and for the - trigger I got 7.13v. As for the voltage of the red I got 11.96v. Thanks Also have a look at the small black wire that I found as it's not connected to anything. I guess I didn't take a picture of the 7.13v of the - trigger. I included a picture of the jack that came from the audio EQ that was removed don't know if this is of any concern.

 

For the + input trigger I got a 2.5mv and for the - trigger I got 7.13v. As for the voltage of the red I got 11.96v. Thanks Also have a look at the small black wire that I found as it's not connected to anything. I guess I didn't take a picture of the 7.13v of the - trigger.

The door trigger measurements should be taken when all doors are open, and then again when all the doors are closed, so we can see the change in voltage levels.

Test 1 for +Trigger.
When all doors are open or any door is open:
The +trigger should change from 2.5mv to ~12v

Test 2 for -Trigger.
When all doors are open or any door is open:
The -Trigger should change from 7.13v(?) to Ground <---seems 7.13v should really be 12v or NC

NC="Not Connected" to anything, or "open circuit".
The 2.5mv readings might be the meter floating, because the door switch signal changes from NC to either 12v or Ground.

The two tests above depend on which door trigger you should be using (i don't know).

Perform the tests and report back...

 

The door trigger measurements should be taken when all doors are open, and then again when all the doors are closed, so we can see the change in voltage levels.

Test 1 for +Trigger.
When all doors are open or any door is open:
The +trigger should change from 2.5mv to ~12v

Test 2 for -Trigger.
When all doors are open or any door is open:
The -Trigger should change from 7.13v(?) to Ground <---seems 7.13v should really be 12v or NC

NC="Not Connected" to anything, or "open circuit".
The 2.5mv readings might be the meter floating, because the door switch signal changes from NC to either 12v or Ground.

The two tests above depend on which door trigger you should be using (i don't know). When you say which type of door trigger? Factory installed is what I know. 1993 GM-Pontiac Grand Prix GTP 2 door . I guess I'll test whit them closed?

Perform the tests and report back...

Please let me know in advance open/close? These test were done with doors open. No the meter was not floating.

 

These test were done with doors open

Ok...then you only need to perform the test with the doors closed.

No the meter was not floating.

How do you know that?
If you connect the meter +lead to +12v and leave the -lead disconnected, what voltage does the meter show?

 

Testing the +input trigger 1.7mv door closed or open. Testing - trigger with both doors closed or open I got 11.90 v

 

Ok...then you only need to perform the test with the doors closed.



How do you know that?
If you connect the meter +lead to +12v and leave the -lead disconnected, what voltage does the meter show?

It floats between 3.0mv down to.7mv something like that

 

Testing the +input trigger 1.7mv door closed or open. Testing - trigger with both doors closed or open I got 11.90 v

Those measurements indicate the door trigger signal is not being received at the alarm door trigger input

do you know which trigger input is used?
In other words, which one is actually connected to the doors?

 

Ok, then you have the results for the test. Doors closed + trigger 1.7mv and -trigger 11.9v. I appreciate your time. Thanks

 

Those measurements indicate the door trigger signal is not being received at the alarm door trigger input

do you know which trigger input is used?
In other words, which one is actually connected to the doors?

Not sure what you mean as I thought both were connected but I guess the alarm is depending on only one door to open in order to disrupt it's circuit and cause the alarm to engage? How can I find the answer to your question? I guess do a continuity/voltage test on the wires going to the door pins and that would rule out bad wires ?

 

Not sure what you mean as I thought both were connected but I guess the alarm is depending on only one door to open in order to disrupt it's circuit and cause the alarm to engage? How can I find the answer to your question? Thanks

Here is how (I think) the door switches should be wired. See diagram below.
The doors in the diagram are shown in the closed position. When any door is opened, the door contact closes and provides either +12 or Ground voltage to the alarm trigger input. But we don't know which trigger signal the doors are wired to provide. There is probably only one type of door trigger used, either a +trigger or -trigger. The top half of the diagram below shows a +door trigger. When any door is opened, it provides a +12 (positive) trigger signal to the alarm. The bottom half of the diagram below shows a -door trigger. When any door is opened, it provides a Ground (negative) trigger signal to the alarm.
We need to determine which signal the doors switch(s) are supposed to provide.

 

Cool I get it, it completes that circuit when opened. each set are parallel circuits? Where do the interior lights come in to play in this system? Also, thanks for that illustration. Or we could say we need to find out which door switch provides the signal. I am done for this evening but I sure hope to see the solution on here some where tomorrow. Thanks

 

Cool I get it, it completes that circuit when opened. each set are parallel circuits? Where do the interior lights come in to play in this system?

I know nothing about interior lights.

Also, thanks for that illustration. Or we could say we need to find out which door switch provides the signal.

We need to find out what the signal is when doors are opened...positive or ground, and confirm it changes when all doors are closed. Then we need to find out if that trigger signal is reaching the appropriate Alarm (either plus or minus) door trigger input connection at the alarm.

 

Does this show the answer? How about this bit of information When the door is closed it creates a open in the ground circuit.

 

That is a Ground issue, the doors pull to ground and self parking on wipers use ground to latch in stop, i would retest ground to the chassis.

I am hoping you can help on this situation and how can I find the answer to these questions. Here is what I have at this point- We need to find out what the signal is when doors are opened...positive or ground, and confirm it changes when all doors are closed. Then we need to find out if that trigger signal is reaching the appropriate Alarm (either plus or minus) door trigger input connection at the alarm.

 

Does this show the answer? How about this bit of information When the door is closed it creates a open in the ground circuit.

Yes. That shows that the signal from the doors changes:

1. from "open" to "Ground" when ANY door is opened
2. from "Ground" to "open" when ALL doors are closed

So...the door signal should connect to the -Door Trigger input on the alarm module.
The -Door Trigger is the "Green" wire on the Alarm module wiring harness.

Test for -Trigger:
When any door is open:
The -Trigger should change from Open to Ground.

Connect the +meter lead to +12v and connect the -meter lead to the -Trigger on the alarm module.
When all the doors are closed, the meter reading should be "floating".
When any door is open, the meter reading should be "+12".

Meanwhile...
Can you post the portion of the schematic that shows the rest of the door wiring? I want to see what else the door switches are connect to...