Fuse Keeps Blowing- advice? |
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Fuse Keeps Blowing- advice? |
mikedsilva |
Mar 15 2015, 05:38 AM
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#1
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Member Group: Members Posts: 90 Joined: 23-February 15 From: Australia Member No.: 18,462 Region Association: Australia and New Zealand |
My new to me, 1970 914/4, has some iffy electrics..
The fuse in the number 7 spot, keeps blowing as soon as I turn the key to ignition on. So, this means I dont have any indicators or wipers working.. etc. Electrics are a little mysterious to me to be honest.. I do have a multimeter.. but I am not sure how to track this problem. I'm thinking I have a short somewhere on one of those systems.. Should I start by trying to unplug each and every component that uses that circuit, then reinstall another fuse, and turn the ignition on? How would an experienced auto electrician pinpoint a problem like this? Any and all advice appreciated.. Cheers Mike. |
BeatNavy |
Mar 15 2015, 06:31 AM
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#2
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region |
I'm certainly no master electrician either but it definitely sounds like you do have a short. Are you sure it's fuse 7? On the '71 Wiring Diagram it shows that that is only part of the license plate light circuit (through the main light switch).
Here's a link you'll need: Wiring Diagrams. Take your time and study this a little. It's hard to see, so you may have to zoom in with your browser when tracing the circuits. You're on the right track with your suggestions. Confirm which fuse and then use these diagrams for your model year to see what's on that circuit or could come into contact with that circuit through something like the main light switch. Remove the license plate light bulbs and see if you're still blowing the fuse. Inspect for spots where wiring insulation may have frayed through and is touching chassis. Let us know what you find. |
mikedsilva |
Mar 16 2015, 05:53 AM
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#3
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Member Group: Members Posts: 90 Joined: 23-February 15 From: Australia Member No.: 18,462 Region Association: Australia and New Zealand |
I'm certainly no master electrician either but it definitely sounds like you do have a short. Are you sure it's fuse 7? On the '71 Wiring Diagram it shows that that is only part of the license plate light circuit (through the main light switch). Sorry, it was fuse number 8.. not 7... i was counting in the low light of the evening (that's my excuse). So many great suggestions.. I've been googling lots and what I ended up using was a 12v bulb connected to two alligator clips.. i then attached these to the fuse terminals. I think the theory of this, is to allow a small amount of current to flow without blowing anything major? Anyhow, with the bulb in place and firmly lit up... i went about wiggling lots of things. I couldnt find the lic plate lights at the rear.. opened the boot and the harness was there.. with the wires taped together! The heatshrink was still around the spade terminals under all the electrical tape, but I was so HOPING that was my short.. Installed a new fuse.. turn on ignition.... POP. gone. My indicators just wouldnt work at all either.. they are all on the same circuit I guess.. My car is missing the wiper switch, (dash mounted knob) so I thought that maybe, a cable was earthing.. when I craned my neck underneath, I could see the switch just barely hanging there, but with no knob. I'm not sure how these switches work.. is full anti-clockwise "off"? I used some pliers to grip the shaft, and turned it anticlockwise.. the bulb dimmed... When I turned it back one click clockwise, the bulb went brighter... when I turned it another position clockwise (I assume this is high speed wipers) it went dim again... So this time, I turned it all the way anti-clockwise again.. put in a fuse.. turned on the ignition and ..... nothing......the fuse didn't blow! Now my indicators are working! The brake lights work, but only on the left side.. i think I have a poor connection where the terminal meets the bulb... Reverse light doesn't work either... yay.... another thing to trace. So, from what I have described, would you say that my wiper motors are shorted/burned out? |
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