Strange Voltage Problems

Michael666 · Post by **Michael666** » 21 Aug 2018, 13:18

I think I might have actually found the culprit. The wire that goes from the alternator to the connector in the fusebox was causing problem. But not the wire itself, nor the fixed part. It seems like the connector inside was causing the issues. After talking to a Volvo service I found out that that wire must have 12V, otherwise the alternator is not charging.
Mine had 0.14V

Took the connector apart, cleaned it, wobbled the cable about...et voilà. 13V and no battery warning. Not even after several starts.

Taking it to work tomorrow again.

Wish me luck. And thousand thanks to all the great advice and help!!!

Michael666 · Post by **Michael666** » 22 Aug 2018, 13:53

I rigged a cable together and, at least while testing, it worked. Not pretty, but a real cable is on the way.
If it works tomorrow for the entire day without a hitch, I guess the problem has finally been solved!!
Maybe even the alternator was a waste.

Post by **SuperHerman** » 22 Aug 2018, 22:39

Good find.

For the final fix maybe see if you can snake it in with the existing wire harness or at least zip tie it along the way. Smart approach is to get the proper gauge wire that is rated for high heat and run a straight piece the entire way and make sure the ends are sealed and secure.

I like to solder the connector then put some dielectric grease on it before sealing with shrink tubing so that corrosion is limited.

All is not lost - you have a fresh alternator and a spare.

Michael666 · Post by **Michael666** » 08 Sep 2018, 08:59

Update. The car got a new battery and runs..BUT something was really draining the battery. On the hunt and with the message "alarm service required" the obvious cause was found.
The pc board is fried.
Can I drive without the Module? I need the car and don't have a new module.

Post by **SuperHerman** » 08 Sep 2018, 13:46

I assume the pic is of your Siren Module. Try cleaning it up w rubbing alcohol and see what you end up with. You might be able to run some traces and get it back running. Basic VOM and solder work. As it is broken no loss.

There are write ups on fixing these and the batteries. Some put the batteries outside the box, properly sealed, to avoid the problem and deal with battery size issues.

As to your question: I believe you can leave the module out (seal the connector). It is no different than pulling the fuse for that circuit. You will lose some functions like sunroof, interior lights and maybe horn. The info chart for the fuse may tell you what is hanging on that circuit. Don’t recall. Leave it out and pull the fuse and do a test of what items you have lost.

Post by **RickHaleParker** » 08 Sep 2018, 21:09

The PC board does look like it might just be contaminated. Contamination can leakage currents, which in turn can cause malfunctions. Clean up with rubbing alcohol and a toothbrush.

Michael666 · Post by **Michael666** » 09 Sep 2018, 08:51

There are actually some little transistors or whatever that are completely burned. There is no saving it. I took the battery out, sealed the box with tape and put it back in for now (until I get a new one). All the functions of the car are there (except that the alarm is probably not going to work) only downside is the fast draining of the battery

Strange Voltage Problems

Re: Strange Voltage Problems