Tmack

Help,
74 with H4 headlight conversion. Drivers side low beam went out last week. High beam is good. But no low beam. Replaced bulb, checked and replaced fuse. Installed a new light switch. cleaned and tightened fuse box connections.Checked bulb harness to fuse box. Still no low beam. Right side everything is fine. All parking, brake, flashers and rear lights are good. Funny thing, high beam indicator light is out also, even though bulb is good. Installed new turn signal high beam switch last year.

Anybody have any suggestions as to what I should look for next?

Tommy

paradisenb

Can't be switch, one light works. Exchange bulbs, i.e. put the left in the right socket, right in left. Same low beam still out? OK. Bulbs are good. Must be in the positive or negative wiring. Most likely the ground is the problem. corrosion. The lamp assembly is probably grounded to the chassis directly or possibly with ground wire. Check these first. Clean well. Next, less likely is positive feed. From switch to lamp-lamp to lamp.

JBrown

take a meter or a test light and see if you are getting power at the bulb plug. there are 3 wires there 1 + for low beam , 1 + for high beam and a common negative for both. test the socket to see what is going on there.

Tmack

Well after replacing the fuse, bulbs, a new light switch, new connectors on the wires which meant removing the washer bottle to get to them and many hours of checking the various wires the problem has been solved. I hope my experience will help someone else. However, I must admit this car is very special to me as it is my first Porshe and it may not be worth much by current standards it is to me. Here goe. This is a 74 widebody cabriolet coversion with a 2.7. and that is the key it a conversion with many upgrades so by no means is it original. It has the h4 headlight upgrades and guess what the problem was! The wiringdiagram on the fuse box cover and the Haines manual do not match the fuse box. Meaning it was the fuse but I never thought to check the other fuses until after all the work. The low beam was wired to another fuse block. Any way its working now and I probably would have had to do the work sometime in the future being the car is 30 years old.

DGaunt

I can confirm that my pretty original '76 911's fuse box bears little resemblnace to the key in the cover, or the haynes or other manuals I have accumulated. These 'mid-year' cars seem to have been wired to some very different diagrams at the factory depending on the equipment installed. It is frustrating and time consuming, but not impossible to work out.

Thanks for the thread. I thought it was just me!