Electrical Nightmares

Par911 · 10-31-2003, 10:38 PM

Anyone ever had any experiences with PO's having after market car alarms that screwed up the electricals? In my case, one of the PO's had a car alarm installed that would make the lights flash the high beams. The alarm was taken off before I bought the car, and now my electricals act wierd. For example if I go over a big bump or pothole, my 911 will cut off, and I lose complete power. It won't start again unless I use jumper wires to bypass the fuel pump relay. Today I started it, noticed some smoke, popped the front hood and my ground wire leading to my fog light relay was fried. A friend looked at it, and said the fuse block is cracked, which may be causing my electrical problems. Is this a correct assumption, anything else I should be checking?

fred cook · fred cook's Garage

Unfortunately, these kinds of problems are not unususal in 911SCs. If you will do a search of this BB on "fuse blocks" and/or electrical problems" you will find lots of comments and solutions.
If the original fuse block is cracked, the simplest solution is to just replace it. Actually, them, as there are 3 separate blocks of fuse holders in an SC. A more complex solution but possibly better in the long run would be to do a conversion to "flat fuse" type fuse holders. In any event, you will continue to have electrical outages until you do some repair work.

Good Luck!

Fred Cook
'80 911SC

weber92037 · weber92037's Garage

I had a similar problem with a rat's nest of wiring and current drain to a dead battery every 10 days or so if the car was not driven. I finally took the car to La Jolla Audio (San Diego). They specialize in Mercedes, Porsche, Ferrari, etc. Might be worth a call to Scott and perhaps he could help over the phone or recommend someone in your area. He is on the Mercedes Shop Forum on the audio section all of the time. Removing my alarm and some other junk restored my courtesy lights in addition to stopping the current drain Good luck,

Par911 · 08:02 PM

Thanks Chuck and Fred, I am looking into converting to flat fuses. Thanks alot for the excel files, they are already coming in handy. I am replacing the fuse block, and hopefully this should alleviate any problems until I get in there to switch up the fuses to flat fuses. Fred, do you think I should switch to flat fuses when I replace the fuse block? Chuck I sent you a PM.

350HP930 · 11-01-2003, 11:10 AM

I have yet to see electrical work from a stereo or alarm job that has not been a complete hack job.

While you do need to make sure your fuse block is OK you will also need to track down all the old splice points for the alarm installation and make sure they are correct, good and insulated.

fred cook · fred cook's Garage

I would not recommend trying to change only part of the fuses to modern type flat fuses. Either do the whole box or stay with the original type fuse holders. If you decide to replace the broken block with a stock piece, be sure to check the wires for corrosion. I found that the wires were corroded back under the insulation about 1/4". By putting in a new stock fuse block and cutting the wire back to clean copper, you should be able to re-establish reasonable quality circuits. HOWEVER, I really believe that changing to the flat fuses is the best way to go.

Good Luck!

Fred Cook
'80 911SC coupe (flat fuse special)

Par911 · 11-09-2003, 04:04 PM

Thanks Fred, I put the new fuse block in. I am planning on changing all of my fuses to flat fuses for my winter project. The files you sent me helped me with putting the new fuse block in. You rock.

Kevin Stewart · 11-09-2003, 04:11 PM

you may have a problem with the factory alarm, which causes the problems you are talking about, when they put new alarms in they dont disconnect the old ones, the problem is its not a just go out and unplug thing, do a search on alarms, thet cause cars to stall and not restart etc etc i had to disconnect my oe alarm because of simular problem you are having, Kevin

Par911 · 11-10-2003, 06:57 AM

Thanks Kevin, I am pretty sure it has something to do with the alarm the PO had on the car, but then had removed. Whoever removed it obviously didn't do a good job of wiring it properly. I hope that after replacing the ignition wires, ground wires, and the fuse block that my problem will be solved