Hi 944 owners,

Owner since 85 of an 83. Spent 8 years in the garage while life took precedent. Got her running last year and been working to restore everything in my skills comfort zone and slowly expanding. Hoping for some help on a lighting problem.

I noticed a few days ago no marker/tail lights front/back. It's possible that one side went out before the other but didn't notice as I don't do much night driving.

Turn signals, brake lights, head lights and fog lights work just fine as does everything else electrically that I know of. When I turn the headlights on, fuses 13 and 14 blow immediately. Nice little fireworks show.

I've cleaned a few grounds that I can get to (By R headlight, battery main ground, rear of engine compartment by firewall, rear by left lights) . I can see grounds under dash, but I see why people say to pull the dash so haven't touched those. I tried disconnecting both rear light harnesses and pulling side marker bulbs on front and testing but they still blow.

Any suggestion where to go next?

 

Fuses blow when there's a short circuit - meaning a power line is shorted to ground. Likely there's a spot where the shielding on the wire is cracked and broken off.

 

Sounds weird that both left and right sides blow at the same time. I would start with removing all the bulbs and using an ohmmeter to ground on the fuse leg going to the bulbs to see if there is a short. Remove the fuse prior to doing this, of course. You should see infinite resistance if all the bulbs are truly off.

BTW, fuses 13 and 14 are for the side marker lights. Do the fuses blow when you turn on the park lights (1st click) or when you turn on the headlights (2nd click)?

 

I'm not sure if it happens at first click or second. I think it was first. I

So I found that if I checked continuity between different positives on the rear lighting connector, I had continuity. I assume I should have zero between differrent positives. I did this with the rear lights discnnected so I did it at the female plug. That supported some of the wires either touching each other or touching ground so I went hunting and before I had to stop for the night for a beer, I found one so far. Now I need to figure out where the wires go after the disappear into the side of the rear seat. Repeat after me... I love my old car.. I love my old car.

My guess is still that I had one side out for a while and the other just decided to catch up with it.

 

Any suggestions for finding other frayed wires other then the obvious looking through dozens of feet of wires after digging them out? Will a tone generator help as it will it pick up more signal when where a wire is frayed?

 

It's very unusual to get short's in two circuits at the same time. Most likely those shorts were human cause. Try to think back about any work that you have done to the car like removing the bumper, bulbs you may have replaced, plugging in electrical connections in backwards, etc. . Also the under the hood light is powered by the left side parking light circuit. I saw that you posted this problem in another forum and it was recommended to replace the headlight switch. This will do zero for the short's. The fuses are after the headlight switch.

 

First - Love the pic. Very nice shine. Been a few years since mine shined like that. Nice to see another 83 silver (I know it's a B/W, but i'm guessing)

Good to know it isn't the switch. The work I did recently was remove the front spoiler for repair and also the front bumper. Human error - Agree that sounds like a good explanation and it's possible they have been out since then. Connectors on side front markers don't matter pos/ground from what I figure/read. The bumper connections are keyed so those can't be wrong. I certainly could have pinched something. Front turn signals work fine as do fog/head.

 

Thanks Marc! Problem solved and it was your advise to retrace the work I had previously done. I kept reading that it doesn't matter which side of the buld is connected to positive or negative and I believe that is correct still, but it does help if you don't connect both the positive and the negative to the connector on the bottom of the bulb for one of your lights. If you are tiried one night putting your spoiler back on, you might just also make that same mistake. This is why removing bulbs didn't fix the issues.

In fixing this, I found a relay on the dash that wasn't connected whic I'll post seperately.

I did fine 3 wires that needed some insulation, a missing forever carpet plug and a missing since I bought the car snap for rear carpet so despite 3 days of frustation, I'm better off now than before.

Anyway... All fixed

 

Good to hear that you got it resolved. Thanks for the compliment. Actually it's Platinum metallic bronze.