blowing fuses

11-13-2002, 03:25 PM

Hey all...
I was driving in the rain in my '85 740 GLE yesterday, had the wipers on, and all of a sudden, my wipers stopped half way up the windshield, and my horn didn't work. I stopped the car, pulled the #15 fuse (25 amps) and replaced it with a fresh one. 5 minutes later, same thing happened. Anyone else had this problem? Is my wiper motor drawing too much current and thus blowing fuses? Do I need to replace it? Any help would be greatly appreciated.
Thanks,
Billy

04-10-2003, 03:49 AM

probably a wiring harness problem. have you replaced it yet? or maybe the connections on the wiper moter are getting wet and shorting out, check it out

04-10-2003, 11:51 AM

Billy,
You're on the right track. You know that the wiper motor and horn are protected by fuse #15. You could check the wiring schematic and see what else is in the circuit, but the wiper motor is at least one thing that you were using when it happened. You also understand that a fuse is a 'current limiting device' and blowing a 25amp one is significant. It may take a few rainy days to isolate, but you may discover it only happens when you use the wipers. Possibly a binding linkage, motor armature bushings, or wiper gearbox (the part that goes through the cowl that the wiper arm attaches to). I would suspect something binding and causing increased current draw. If it is built like the 240s (someone confirm this) first remove the wiper arms, unbolt the motor, take the nut off the drive cable housing, and remove the motor,pulling out the drive cable along with it. The gearboxes will rotate as the cable is pulled out. Check them for binds. There are no gears , just a shaft in a bushing. These can corrode and increase the motors effort. Lubricate them PB Blaster,WD-40 to loosen them up. In fact, if you don't want to go through this, just lub them anyway and your problem may disappear. Another idea.....just run the wipers on your dry (clean) windscreen. That adds a lot of resistance, but the motor should be able to do it. If the fuse blows, you have isolated the problem. Have Fun!! Good Luck.

growley · 04-10-2003, 03:27 PM

Funny you said that, it was raining here yesterday, I started my car and it stumbled hard and my service light came on for about half a second. Then when I was driving later, the car stumbled again and did the same thing. I had only blown a vital fuse. Check yours with a test light.

04-10-2003, 05:40 PM

Billy..........SORRY......I'm geezing BIG time. That wiper drive configuration I described was for ENGLISH cars....MY APPOLIGIES....I'll just be quiet and read now.

gecko · 04-10-2003, 11:14 PM

sounds like the circuit for fuse #15 is shorted to ground somewhere.....get out your test light or dvom and have at it

neal

04-10-2003, 03:27 PM	#4
growley has a large member Join Date: Dec 2002 Location: Seattle, WA	Funny you said that, it was raining here yesterday, I started my car and it stumbled hard and my service light came on for about half a second. Then when I was driving later, the car stumbled again and did the same thing. I had only blown a vital fuse. Check yours with a test light. __________________ -Ian '91 240-"slolvo" Gnargineering

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11-13-2002, 03:25 PM	#1
Anonymous Guest	Hey all... I was driving in the rain in my '85 740 GLE yesterday, had the wipers on, and all of a sudden, my wipers stopped half way up the windshield, and my horn didn't work. I stopped the car, pulled the #15 fuse (25 amps) and replaced it with a fresh one. 5 minutes later, same thing happened. Anyone else had this problem? Is my wiper motor drawing too much current and thus blowing fuses? Do I need to replace it? Any help would be greatly appreciated. Thanks, Billy

04-10-2003, 03:49 AM	#2
Anonymous Guest	probably a wiring harness problem. have you replaced it yet? or maybe the connections on the wiper moter are getting wet and shorting out, check it out

04-10-2003, 11:51 AM	#3
Guest	Billy, You're on the right track. You know that the wiper motor and horn are protected by fuse #15. You could check the wiring schematic and see what else is in the circuit, but the wiper motor is at least one thing that you were using when it happened. You also understand that a fuse is a 'current limiting device' and blowing a 25amp one is significant. It may take a few rainy days to isolate, but you may discover it only happens when you use the wipers. Possibly a binding linkage, motor armature bushings, or wiper gearbox (the part that goes through the cowl that the wiper arm attaches to). I would suspect something binding and causing increased current draw. If it is built like the 240s (someone confirm this) first remove the wiper arms, unbolt the motor, take the nut off the drive cable housing, and remove the motor,pulling out the drive cable along with it. The gearboxes will rotate as the cable is pulled out. Check them for binds. There are no gears , just a shaft in a bushing. These can corrode and increase the motors effort. Lubricate them PB Blaster,WD-40 to loosen them up. In fact, if you don't want to go through this, just lub them anyway and your problem may disappear. Another idea.....just run the wipers on your dry (clean) windscreen. That adds a lot of resistance, but the motor should be able to do it. If the fuse blows, you have isolated the problem. Have Fun!! Good Luck.

04-10-2003, 05:40 PM	#5
Guest	Billy..........SORRY......I'm geezing BIG time. That wiper drive configuration I described was for ENGLISH cars....MY APPOLIGIES....I'll just be quiet and read now.

04-10-2003, 11:14 PM	#6
gecko Board Member Join Date: Nov 2002 Location: N. VA	sounds like the circuit for fuse #15 is shorted to ground somewhere.....get out your test light or dvom and have at it neal