screeching sound like fan is catching

[BEJinFbk]

AFAIK, there's no single diagram for it. But there are plenty of clues.
The PNP shows up in the diagrams for any system that it's a part of.

There may be more Pos ll 12 volt sources than the back-up light supply in the PNP,
but that one is definitely tied to the operation of the ignition switch in "run".

[cn90]

OK MadeinJapan,

Time to clean your PNP Switch and report back:

https://www.matthewsvolvosite.com/forums ... =1&t=29930

https://www.matthewsvolvosite.com/forums ... =1&t=29921

[MadeInJapan]

...Here's another question/experiment for you -
Key on in the run position, motor off, green wire unplugged from the starter:
what's the reading at the green wire's connector? Any voltage? There shouldn't be.

1+,

First, d/c the green wire from starter and measure Voltage (not Ohms) between ground and the tip of green wire.
The factory design is:

Report back what green wire voltage (not Ohms):
- Position I: should be 0V
- Position II: should be 0V
- Position III: should be 12V

I suspect the green wire @ Position II ---> 12V! Which causes this saga.

Anyhow, trouble-shooting electric problems requires:
- Good understanding of electrical circuit
- Difference between Volts and Ohms.
- Proper use of Multimeter
- Good understanding of the engineers' design of the car
- Good understanding of relays
- Good understanding of connector: easy to get confused... A good trick is to hold the relay up and with a piece of paper map the corresponding sockets terminals. Always refer to the piece of paper, so instead of looking at the socket, you look at your diagram on the paper.

Wow, I'm overwhelmed at the number of posts and things to try.
First off, I'm not going to pull things out and start testing the PNP switch...that would be one of the last things I do. I just don't have the energy or time...besides, the battery was new at the beginning of the summer and it is sealed- no acid has or is going to spill.

Now, to the questions here- at position II, yes the green wire has 12.5v and it show zero. I can test it in III but I don't have someone nearby to help me right now- I would think it would be the same voltage. Btw, my battery is 12.5V between positive and negative terminals. Oh, and yes, I got tired of turning that relay over last night so I have already done the piece of paper trick...it is much easier.

[MadeInJapan]

MadeinJapan,

Do a quick test for me.

- Leave key OUT of ignition. Put everything back (green wire connected to Starter, Starter RELAY back in place).

- Open the upper fusebox near the driver windshield glass. This is the place for Cruise Control Relay Module, Fuel Relay etc.

- Turn key to position II, your starter will run (as you said earlier). Pull the Cruise Control Relay Module, does the starter stop running now?

Volvorelays.JPG

I pulled the cruise control relay (double wide) after starting in position II and it made no difference.
For kicks, I tried to start the car with the relay out and same thing- the starter ran and continued to run until I disconnected the wire (or turned the key back to position I and off).

[MadeInJapan]

...The fuse that controls the IAC, MAF, the Injectors and the Control Module Power Supply keeps blowing too. It's somewhere in this circuit but I can't figure it out...

Look at the diagram below, EXACTLY which fuse blew when this whole saga happened?

VolvoRelay.JPG

#11 fuse (10A) which is listed as a fuel injector fuse but if you read up on it, it does more than that- it also controls the idle air control and the MAF as well as central power supply (or something like that- whatever that is).

[MadeInJapan]

MadeinJapan,

Do a quick test for me.

- Leave key OUT of ignition. Put everything back (green wire connected to Starter, Starter RELAY back in place).

- Open the upper fusebox near the driver windshield glass. This is the place for Cruise Control Relay Module, Fuel Relay etc.

- Turn key to position II, your starter will run (as you said earlier). Pull the Cruise Control Relay Module, does the starter stop running now?

To clarify -
As I understand this problem, the starter only
overruns AFTER it has been initially engaged.

I don't know about "overrunning," as you call it- it just never disengages.

[MadeInJapan]

I really want to avoid getting into the PNP switch if possible- this is time consuming and laborious-
I have replaced these before- they don't just "go..." They become funky and take rocking the shifter, etc. to get the car to start...My problem is the opposite. I have never had an issue with the PNP switch in my car. Now, wire cap coming off the end of the electrical portion of the ignition switch- that could be a great place for me to look- something I have not done. I could take the cap off and take a look- just need to be careful...I understand that those parts can fall off and getting the colored wires back could be problematic.

I have been saying all along- I think it's a positive short below all the circuitry that controls the starter, which I believe is functioning properly. Where does the green wire come from anyway? Alternator? If so, maybe I should see if a live wire is shorting out to the chassis of the alternator.

[cn90]

...Now, to the questions here- at position II, yes the green wire has 12.5v and it show zero...

With key in position II (don't start the car), the green wire has 12V or 0V?
Please clarify.

----------
So if I can summarize everything:
1- In one of the posts below, you said: "position II, socket #87 has 0 volts".
2- Now the green wire feeding the starter: "position II, it has 12 V".

Please review the electrical diagram I posted in page 2 of this long thread.

Socket #87 ---> PNP ---> Green wire to starter

That is the bottom line!

If both of these statements are true then the culprit is in between, i.e., either:
a. the wiring between the relay socket and the PNP
b. the PNP itself
c. the wiring between the PNP and the starter.

It is your choice lol.

[MadeInJapan]

...Now, to the questions here- at position II, yes the green wire has 12.5v and it show zero...

With key in position II (don't start the car), the green wire has 12V or 0V?
Please clarify.

It has 12.5V...not 0- I meant to say it should have 0

[cn90]

Then you already nailed the problem.

Key in position II:
- Socket 87 is 0 volts
- Green wire at starter has 12 V (when it should be 0 volts).

So the problem is as I mentioned above, it is either a), b), or c).
It is beginning to sound like PNP, but again PNP virtually does not do this unless there is some bizarre things going on inside the PNP switch.

If you want to simplify your life while waiting for a permanent fix:
- disconnect the factory green wire at the starter.
- remove the relay for now.
- run a separate green wire from the socket #86 (yes 86 and not 87) to the starter. People who bypasses PNP switch do this.
- just remember to start your car only in P or N!!!

The early models (1994-?1996) have no starter relay at all.