Strange Voltage Problems

Post by **mrbrian200** » 11 Aug 2018, 13:15

That wire tap somebody added breaks the insulation around the wire, moisture and road salt gets in and can rot the copper wire. It is quite possible that the small wire (it runs between the alternator and CEM) has degraded. If your alternator uses the 'old school' analog signal across this wire (not LIN data), in '02 I'm not sure what it is, then resistance across this wire could cause the headaches you're experiencing. On the newer LIN data controlled alternators communication between the alternator and the CEM tends to follow the rule of it works or it doesn't.

Those sorts of wire taps are only suitable for use inside the passenger cabin. For exterior/engine compartment wire taps you need the ones that are filled with silicone sealant or solder and seal with shrink tubing over silicone or poly sealant. You will observe that the terminal cimps of the ground wires that attach to the inside of the fender are sealed inside molded plastic . Note Volvo kind of messed up on the heavy power/ground battery cables under the hood (they sealed around the terminal crimp with shrink tubing but left the end open for water and salt to wick up into the stranded wire). Hence they are known go bad as the vehicles age. The other end of the cables, largely protected from moisture and salt in the trunk, is fine as is.

Post by **SuperHerman** » 11 Aug 2018, 13:23

I assume the wire you posted a picture of is the same as figure #3 in this article: https://www.pelicanparts.com/techarticl ... cement.htm

As mrbrian200 states this goes to the CEM and controls charging.

You need to repair this correctly. If you have the end that plugs into the alternator sometimes you can open these up and reuse them. Takes some care and time. Then find a suitable gauge wire and properly spice it in - not with that blue thing. Personally I would solder the wire and shrink wrap it. Go back far enough where the wire you are working with is not oxidized.

This has a strong possibility of being your issue. Either way it needs to be sorted through correctly.

Michael666 · Post by **Michael666** » 11 Aug 2018, 14:12

I was afraid that that wire tap could be the problem. I'll try and fix that properly but I will also get the alternator checked while it's out I might as well.

Post by **mrbrian200** » 12 Aug 2018, 00:35

You'll probably want to cut it 5-10cm above where the tap was and splice a new wire/terminal onto your harness correctly (sealed). I don't know if Volvo sells just this wire with a terminal already attached as a replacement part. Be careful of terminals sold in various retail stores - many of them aren't rust/corrosion resistant and can degrade in a matter of months.

If you go the make your own route, look for marine grade terminals, crimp the wire onto the back of the terminal then solder it with lead free silver bearing solder. Solder where you splice it onto the vehicle harness then seal it up. Note: black electrical tape does not hold a seal for the long term. You have to encapsulate it with silicone or some form of poly.

Post by **RickHaleParker** » 12 Aug 2018, 12:34

I am old enough to recall when Quick Wire Connectors first came out. The manufacturers advertised them as temporary fixes, few people listened to that part.

Quick and Crimp electrical connectors do not make good permanent connections, they where not engineered to be permanent.

Michael666 · Post by **Michael666** » 20 Aug 2018, 12:22

The next "problem" is now here. I fixed the wire, everything checked out. I replaced the alternator. It came with a new regulator aswell. It ran fine....14.4V. Shut her off, cleaned up, went for a test drive...still everything as it should be. Then i got my wallet and went to the supermarket, no issues. Started the car and that stupid battery warning came back on but turned off after driving for about 20 seconds and stayed off. I checked the tire pressures, and wanted to drive home. same thing happened. Battery warning light, left the parking lot, light turned off and stayed off.
WHY does my Volvo hate me?!!?

Post by **SuperHerman** » 20 Aug 2018, 20:47

I think you have to look at your battery again. Any chance you can borrow something that will fit and see how it fairs? The earlier problems could have harmed the battery.

Other than that check all your cables and ground straps. Last is you have an issue with some module which is beyond my knowledge.

Post by **RickHaleParker** » 20 Aug 2018, 22:19

Are you 100% sure it is the battery light that is coming on? The low coolant light looks alot like the battery light.

WHY does my Volvo hate me?!!?

It is like having a wife, she reserves the right to change her mind.

Michael666 · Post by **Michael666** » 21 Aug 2018, 01:21

Yes I'm 100% sure. The coolant warning came on as well, but that is no problem. Just had to top it up.
Took the car to work this morning. The first 900m were nailbiting with a lot of angry words, but the warning light turned off and I had a nice 40km cruise without a single warning light.
It is just the first few hundred meters.

Post by **RickHaleParker** » 21 Aug 2018, 04:04

Have you check the battery light against a Multimeter?

Strange Voltage Problems

Re: Strange Voltage Problems