Impala Tech - View Single Post - complete electrical shut down
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post #5 of (permalink) Old 02-09-2019, 04:30 PM Thread Starter
japete92
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Join Date: Dec 2012
Location: virginia
Posts: 354
 
Quote:
Originally Posted by Big Dave View Post
Pete you bought a car that is over a half century old. The wiring was inadequate when new. GM cut every wire to length with little give because copper costs money. Money they would rather keep for themselves. For the same reason they used wire that was too small of a gauge to carry the load the distance required but they figured no one would notice. Fire departments noticed but they didn't buy cars.

In your case the load you placed on your wiring blew the fuse because of corrosion. The fuse is bundled in the actual wiring as a fusible link. You can replace it but the next time you touch that dimmer switch I will bet it blows again; because the switch has shorted out. So I would replace the dimmer switch first, then replace the fusible link.

You need to determine the amperage rating of the fusible link before you go to your corner Chinese import auto parts store (refer to your service manual for rating and were to find it).

https://shop.advanceautoparts.com/p/...621/22141316-P

Personally I do not like fuses. I prefer to use a circuit breaker that will keep your car from burning to the ground but not leave you stranded on the side of the road needing a tow home.

https://www.delcity.net/store/12V-Au...SABEgITMfD_BwE

They come in amperage ratings of 5 to 75 AMPs (once again you ptotect the circuit by determining it's capacity (load and wire size/distance). The longer you run a wire the bigger it has to be. If you add circuit loads (such as electric fans or fuel pumps, etc.) you have to increase fuse size and wire size at the same time.

Big Dave

Big Dave,

Thanks again for your input.

An update:

Today (after looking at the wiring diagram and the car) I tried the horn because it looks like all power runs thru the horn relay; nothing. I disconnected the two 12 gauge wires I had connected yesterday, chose the oldest looking one, and connected it directly to the cable clamp bolt. Power was restored. Not enough to crank the car but I jumped the battery and the car instantly started.

I've concluded that the short 'little' wire on the battery cable (that I used to connect the two wires I have) must have been a fusible link. I have no idea what its 'rating' was. The wire I did not use (the newer looking one) appears to power the power seat because that does not now work (everything else does).

My question: The 'run' for the 12 gauge wire from the horn relay to the battery clamp is approx 40 inches. If I were to add one of those circuit breakers from you post, what rating would you recommend?

Thanks.

Pete
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