Blown fuses

tlarson · #1 (**permalink**) 08-24-2009, 05:35 PM

Ref: 1994 164

We keep blowing the 10 amp fuses for the tail lights. They are number 1 and number 2 in the fuse panel under the steering wheel.

Here's how they are listed in the manual:

Number 1: Right front marker light and left tail light - License plate light - Cigar lighter

Number 2: Left front marker light and right tail light - Marker light indicator - Instrument panel lighting - Vanity mirror light

They usually fail together.

If there is a methodical way to troubleshoot this problem I'd like to know about it.

Any help would be appreciated. Thanks.....

164 FAMILY · #2 (**permalink**) 08-28-2009, 02:20 AM

Check the front and rear bulbs for rust/corrosion. You might want to try the lighting control unit under the glove compartment.

AlexGS · #3 (**permalink**) 08-28-2009, 08:46 PM

Hopefully there is a logical explanation, such as a crack in a rear light unit and the bulbholder full of water.

If all the lights check out OK, check the illumination of all console items, such as the cigarette lighter. The bulb holder is a little haphazard and I imagine it would be quite easy to have a short circuit there, which is on the same fuse as the tail lights. US cars have four additional side marker lights (I think?) as well as the front and rear lights, so all the more places for possible shorts and water-filled bulbholders.

I think the funniest 'blown fuse' problem I ever solved was a cigarette lighter socket that had been used to store small coins (and was therefore a dead short!)

-Alex

tlarson · #4 (**permalink**) 08-30-2009, 08:09 PM

I've checked all the bulbs and they're fine. I'm beginning to suspect the lighting control unit, but can't find it anywhere, or even ID it. Only marks on it are "A727 558" It has seven pins on the back. Any idea where to buy this? None of the local or specialty auto parts houses has it. Thanks....

164 FAMILY · #5 (**permalink**) 08-30-2009, 08:32 PM

I have a good working used one.

tlarson · #6 (**permalink**) 09-06-2009, 11:36 AM

I raplaced the lighting control unit (found one locally) and am still blowing fuses. The fuse that immediately fails is the 10 amp fuse in position number 2: Left front marker light and right tail light - Marker light indicator - Instrument panel lighting - Vanity mirror light.

This is driving me crazy. Any ideas?

**Alfisto Steve** · #7 (**permalink**) 09-06-2009, 11:45 AM

Quote:

Originally Posted by tlarson

I raplaced the lighting control unit (found one locally) and am still blowing fuses. The fuse that immediately fails is the 10 amp fuse in position number 2: Left front marker light and right tail light - Marker light indicator - Instrument panel lighting - Vanity mirror light.

This is driving me crazy. Any ideas?

AlexGS · #8 (**permalink**) 09-06-2009, 03:09 PM

Somewhere behind the stereo, there is a grey wire that carries the instrument lighting power. Many aftermarket stereos do not use this wire - perhaps it is shorted to ground?

-Alex

**ChazzyD** · #9 (**permalink**) 09-06-2009, 04:10 PM

Quote:

Originally Posted by AlexGS

Somewhere behind the stereo, there is a grey wire that carries the instrument lighting power. Many aftermarket stereos do not use this wire - perhaps it is shorted to ground?

-Alex

AlexGS · #10 (**permalink**) 09-06-2009, 05:48 PM

Quote:

Originally Posted by ChazzyD

Now that is a good possibility.

Charles

MrT · #11 (**permalink**) 09-06-2009, 10:29 PM

I had an interior light problem on a '63 Volvo (admittedly not even a Volvo 164) caused by a pinched hot wire at the light fixture. Intermittent short to ground. Quite akin to the illumination wiring behind radio suggestion above. Good luck finding it. You could probably disconnect the power leads going to the various lights and see which power feed is Doing The Deed.

Michael

tlarson · #12 (**permalink**) 09-11-2009, 09:36 AM

Found the problem. Passenger side visor wire was shorting. Don't need the visor light, so we just disconnected the wires at the local connector and taped up the end. That way we can put a new light/harness in later if we choose.

Thanks to all who helped/made suggestions.

**Alfisto Steve** · #13 (**permalink**) 09-11-2009, 09:49 AM

Quote:

Originally Posted by tlarson

Found the problem. Passenger side visor wire was shorting. Don't need the visor light, so we just disconnected the wires at the local connector and taped up the end. That way we can put a new light/harness in later if we choose.

Thanks to all who helped/made suggestions.

tlarson · #14 (**permalink**) 09-12-2009, 06:27 PM

Thanks, Steve. You were spot on....

Because of my lack of knowledge of this car I may never make a decent contribution to this forum. The least I can do is update you on what we find.