Short Finder tool

They say if you don;t use something in year you should get rid of it.  Well I don’t take that advice on tools. I can;t remember how many years its been since I last used this tool but today it was really handy to have.

When I was trying to figure out the trouble with my Porsche tail lights I found the at the previous wonder had modified the wiring for the left side tail light.  Also, the front corner markers have never worked since I have had the car.

Tracing the circuit, I found a dead short int he left side wiring that would blow the fuse. I assume this is the reason why they have jumpered the tail light wires and disabled the front markers.

Using the above tool, I was able to trace the short to somewhere in the front fender area. Without it I would have just been guessing.

I made a jumper to use the tool to put power to the load side of the fuse and took power straight off the battery. Since there was a dead short I did not want to stress the light switch while searching for the short.

I was able to use the little meter to follow the wire through the car and down into the fender. I then put the car on the lift and removed the belly pan to get access to the wire. Since there was just a short section of wire to inspect I decided to do a visual inspection instead of continuing with the tool.

It took some searching, but I finally found the problem.  The wires inside the left side marker were twisted together and the ground was touching the power lead inside the rubber cover.

I hooked them back up correctly and the short went away.  I then redid the wiring at the tail lights to put it back like the factory intended. now there is a fuse for the left and a fuse for the right. And a another fuse for the tag lights.  Germans like fuses I guess.

Thanks goodness I had this handy Short Circuit finder tool.

944 Tail lights don’t work

Repairing my 944 tail lights – Tail light fuse late 944

944 tail light

After my last trip to AMP for track night, I ended up having to drive my race car home due to a tow vehicle failure.  Halfway home, I stopped to eat and noticed the tail lights were not working.  However, I had two very nice tag lights so I elected to make it home anyway.

Last night I decided to dig into why the tail lights were not working. I expected to find a loose wire or failed bulb.  Neither of these was the case.

I then decide to check the fuses and after searching the inside of the fuse box and several internet searches, I could not find a listing for the tail light fuse.   I read through a couple of forums and still no mention of a tail light fuse.

So next I printed out the wiring diagrams.  These are hard for me to follow but even more so in that, the individual bulb functions are not listed on the diagram.  It shows all the bulbs in the tail light housing but not what each one does.

So I pulled the tail lamp assemblies apart and traced the wires from the non-functioning bulbs to the connector and determined the wire color on the harness side fo the connector.  That is when I noticed that a previous owner had redone the wiring so that the left side tail light was jumpered to the right side taillight. I found that odd but continued.

I finally figured out that the tail light bulbs also power the side markers. I don’t have side markers on the race car but I do still have the plugs dangling from the tail light housings.  I remembered seeing a side marker fuse listed when I was researching.

So fuse 40 and 41 are listed for the side markers.  Sure enough, both these fuses were blown. I tried replacing fuse 40 and it would instantly pop indicating a dead short.  Fuse 41 seem loose.

After tracing the wiring diagram again, I figured out why the previous owner had jumpered the two tail lights together.  The left side marker circuit has a dead short.  So he powered the left side off the right side.

I then replaced the fuse for the right side marker circuit and wiggled it around to get it to seat properly.  After some wiggling of connectors in the rear of the car again had tail lights on both sides.

I will later go back and see if I can locate the short in the left side circuit. I expect this is why my left front marker has never worked.