I have a 1999 S80 with 124,000 miles on it. I found ouit later after I bought it that it has this electrical issue I have yet to find anything simaler on this forum. So I am going to see if anyone can help diagnose this problem I am having... So here it goes....

What does not work:
Sunroof, remote, the AC console light panel

What works but only intermediate:
The overhead cabin lights > what is strange is that these lights only work when I pull the fuse and reinstall it the cabin lights will work. After 5 min of driving or if I turn the car off and restart it the cabin lights will not work. If I check the fuse it is NOT blown, if I repaet the process the issue will start all over again.

The other strange thing is that the headlights will work both in the on and off position. If I set the lights to the hollow "O" position (which should be off) the light are on. The only way to turn the lights off are by turning the ignition off. The other thing is that I hear a clicking sound at a electrical box at the radiator fan when I turn the engine off. It will click 5 times that quit. Sometimes if I sit in the car at night I hear a high pitch (very faint) hum sound without the key in the ignition. Also A couple days ago I was taking the car for a strut repair and I had it on an incline (front nose downward) and I had the keys in my hand, and all of a sudden the doors auto locked. I tried the key fob... nothing! WILD!

So would it be a relay giving the issue? What in the heck could it be. I have tried resetting the computer by the door locks, that does not do the trick. I have had a new battery put it, that did not do the trick.

It is like parts of the car falls asleep, it does not drop any fault codes. I do not have any messages on the screen. The car drives fine.... Please help!

 

low battery voltage probably. CCM not talking the way it should. Could also be in the immobilizer system. Its had to tell with out looking at the values with a scan tool.

 

Are there any after market electrical devices installed on this vehicle? If so check all associated wiring. Use a hair dryer to dry out all fuse panels. Have you checked all relays in fuse/relay panels? Check under dash, console, trunk for wiring problems, most are associated to a faulty ground. Do you have any repair books on the vehicle?

 

first I would like to say in advance, Thank you for your continued responses!


MSGTUSMC:

To my knowledge there are no aftermarket devices on the vehicle. I have checked the fuses and all relays. I have not see any moisture on any of the boxes. I have looked at the wiring harness under the dash and console, nothing that seems to indicate an issue. The only book I have is a Hynes book I purchased off the net. I really does not give hardly enough electrical troubleshooting.

Lifesgoodhere:

low battery voltage probably. CCM not talking the way it should. Could also be in the immobilizer system. Its had to tell with out looking at the values with a scan tool.

A) would an alternator check reveal a low voltage draw? What and where is the immobilizer system, are you referring to the alarm system? What scan tool are you recommending?

Please advise

 

The only scan tools out there that will read what you need to dignose this problem correctly is an:

Autologic. Costs $12,000 for just the computer and $7,000 for the software for each make of car. I have one.

VADIS: OEM scan tool software. The scan tool cost $70,000 and you have to buy software for each model and year of Volvo car. I think it costs $6000 per model per year. (note you can buy/download pirated versions, but they are all carp)

With my Autologic I can do everything a dealer can with the exception of key programming.

Go to a dealer.

 

Try unlocking and locking with remote of the car. it works all the time in mine 99S80. Also that car has DRL known as day running lights The dealer can made this off by connecting their computer.

 

The key fob (remote) does not work.....

 

Well. I would go to a dealer, however the closest one to me is about 125 miles. That is why I am trying to troubleshoot on this forum.....

 

Try and get some batteries or get a remote replacement, they r pretty cheap on ebay. My s80 does that sometimes, audio control, sunroof and the interior lights the top one stops working i usually click the unlock and lock on the remote and it works. I think it has to do with the alarm module going bad! But im not sure.

 

try doing a hard battery reset, and buying a new battery.the longer you let the car sit with the pos and neg cables clamped together with vise grips the deeper the reset goes into the computer.

 

Really! Ok; so I bought a new battery about 5 months ago, that should be ok.... You think? So all I need to do is undo the pos/neg at the trunk battery, and clamp them together. For how long your you recommend I leave it clamped? and which cable do I install back on the battery pos or neg... Do I need to doe any thing with the door locks and/or Key positioning after the cable reset? I will try it this weekend, maybe tonight!

 

I tried the hard reset and I let it set for an hour... It didn't work. As a matter of fact when I touched the pos/neg together, there was no spark. I guess I am back to the drawing board..!

 

Electrical issues can be frustrating. Your issues appear quite minor, however. Have you checked the bulb(s) for the AC console light panel?

The place to start if you have no other information is by checking grounds. Get your hands on the electrical schematics for your car. Identify the circuits that the devices you mention above are on. Locate the grounds for those circuits on the schematic and then locate them on the car. If it turns out that all the problem devices share a ground, that's a clue. Disconnect the grounds, clean them up and reinstall.

Other ideas. Sunroof - mechanical problem? Overhead cabin lights - door switch?

 

doesn't happen every time, its very small and quick.

If that didn't work, you need to go to the dealer, and get them to straighten it out. Could be in the computer, wiring who knows.