Fuse constantly blowing

Hello, I've got a 1979 300SD which has an electrical problem. The fuse that runs the brake lights, turn signals, and fuel gauge keeps blowing. I looked in the trunk at the brake lights and unhooked a trailer brake light harness, because I thought that might be it...but it was not. Any suggestions? thanks, Jeff

Forums

Body and Interior Specific Aid

Taxonomy upgrade extras

Questions and Answers

Chassis Model Number

W116

Need more info

Hi Jeff, when does the fuse blow? This may give further clues to the problem.

Not sure

I've been trying to figure that one out. It always seems to blow when I'm not paying attention. I went and did a test today and it wouldn't blow. It might be the left turn signal, because sometimes that signal will blink quickly as if the bulb is burned out, of course it is not. I took that bulb out and looked at it as well as the socket, and nothing seemed out of place. I do however get water in my trunk from time to time, I think it may have something to do with that. I'll keep looking. Thanks again, Jeff

Start by unplugging circuits

You might start by unplugging one tail light wiring plug at a time to see what happens. You might also be suspicious of the Hazard/Flasher unit in the center console (since your flasher seems to be acting up). I have some good used units if you need one.

I've had the same problem- different area

Hi Kent and Kaia, Brook here from San Diego (Justin Mans girlfriend)... My '82 300D does the same thing...the fuse that runs the blower for the fresh air and air conditioning will run fine for an hour or two and then it goes. I've replaced it many times and sometimes it will "hold" for a long time (weeks) and other times, it just blows again and again after running for a half hour or so and changing the fuse.... Any ideas? It drives me nuts in our hotter Southern California weather. It's been a hot summer and I need the AC!!

Suspect blower motor

Hi Brook, I have seen this same condition a number of times before and it is almost always solved by replacing the blower motor. Your motor is probably drawing too much current (due to age and possible internal problems). You could take the motor out and have it tested at an electrical repair shop to be sure. We do have new motors available with instructions on how to replace it yourself. (Not a difficult job). Kent