complete electrical shut down - Impala Tech
Electrical & Wiring Troubleshooting electrical problems

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  • 1 Post By japete92
 
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post #1 of 10 (permalink) Old 02-08-2019, 02:44 PM Thread Starter
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complete electrical shut down

Something very strange just happened to my '63 Impala. I'm not much of an electrician so some help is solicited.

I'll explain (sorry for the long post):

I have been having some problems with the car not holding a charge. All last summer I simply disconnected the battery every time I parked the car in the garage. It would always start right up and ran great.

About 2 months ago I had the car in the shop for some body work. The folks had trouble starting the car, checked the battery, and found it unable to hold a charge. A new battery was installed (after they checked the alternator and voltage regulator). When I got the car back, everything was great. It sat once for almost two weeks one time and it started immediately. Hurray.

Last week, the car would not crank after sitting about 4 days. I began checking for some obvious wiring defects and discovered an interesting configuration. There were two (approx 12 gauge) wires coming from the positive battery clamp (along with the 2 gauge wire to the starter). One went into the harness and appeared to be connected to the voltage regulator. The other looked like it was external to the harness but was wrapped (using electrical tape) to the harness. I tried to follow it and it appeared to go thru the fire wall with the harness. But I'm not at all confident that is correct. And I could not track it inside the car.

The insulation on one of those wires was worn down to the copper wire and the copper wire was almost completely corroded through (only a strand or two intact). The other was fine. I looked up the wiring diagram and it shows only one 12 gauge wire from the positive clamp and it goes to the voltage regulator.

To re-state. All this time the car ran great, no electrical problems except for the battery drain and/or bad battery, which only impacted starting.

I bought a new battery cable w/one 12 gauge wire coming from it. I installed today and I connected both the old 12 gauge wires to that one. Jumped the car; started immediately. Hurray (again short lived).

I drove the car for about an hour to charge the battery. Car drove/ran great. Got home pulled into the garage and began a few checks. Turned on the headlights; ok. Hit the dimmer switch to turn on the high beams and the car immediately stopped running and everything went dark. No electricity running to anything. Even the dash warning lights would not illuminate with the ignition switch 'on'. Jumped the car and absolutely NOTHING.

What in the world did I do? What would fail and cause this? It's like some complete electrical system circuit breaker tripped (or fuse blew). Is there such a component?

Thanks and I again apologize for the long post.

Pete
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post #2 of 10 (permalink) Old 02-08-2019, 03:46 PM
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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
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post #3 of 10 (permalink) Old 02-08-2019, 04:22 PM Thread Starter
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Big Dave,

Thanks.

Reading electrical diagrams is not one of my strengths. I went looking for the fusible link on the wiring diagram in the shop manual and could not find it. Where (on the car) is it located. And where may I find the rating it should be?

Your idea of a circuit breaker makes a lot of sense. I may go that way.

Thanks again.

Pete
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post #4 of 10 (permalink) Old 02-08-2019, 05:34 PM
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I do not know where it is on a 1963 (In 1963 I was building '55 Chevys with 331 or 336 engines). But you can usually find it by looking for the chard plastic wrap, or an area that bubbled up with a hole in it to let the sacred smoke out.

The fusible link burns open with a lot of heat. So it usually leaves evidence of it's demise.

Big Dave
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post #5 of 10 (permalink) Old 02-09-2019, 04:30 PM Thread Starter
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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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post #6 of 10 (permalink) Old 02-09-2019, 06:35 PM
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12 guage copper multi-strand wire can handle 25 AMPs at 0-5 feet of length, though that factory wire is expected to carry 30 Amps (which is why I mentioned the factory undersized wires). A 12 gauge copper multi-strand wire used as a fuse (less than a half inch long) can handle 235 Amps before melting (why the factory though they couyld get away with under sizing wire)

Read this "NAPA know how" to size and identify automotive wires.

Know-How Notes: Automotive Wiring Guide - NAPA Know How Blog

Big Dave
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post #7 of 10 (permalink) Old 02-09-2019, 06:45 PM
BA.
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You have a tough issue there for sure and there's certainly enough expertise here to get you through it.

Since you're in the middle of a potential fix, I just want to drop these 3 comments until we hear how your new wire run works out.

1. I am with Dave, due to personal experience, that you really should replace that Dimmer switch. They get faulty, cause grave issues, and they are cheap and easy to replace. Do it.

2. Bear in mind that you very well could have more than one issue. Don't let yourself get stuck on a single solution that solves everything.
3. Personally, I really really think you should find out where that mysterious 2nd small wire is going to from your battery post. It might be as simple as a home-run for a radio, or old switch someone installed, or hell, the key itself. People do weird things. If you can crimp or solder a wire (any monkey can!) than you might even consider just cutting it or removing it at the battery and you'll soon figure out what it was for if it serves any importance.




Cheers! Good Luck! Keep us up-to-date!

HOW A NOVICE REBUILDS A 66 IMPALA CONVERTIBLE:
http://www.impalas.net/forums/blog.php?u=1432
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post #8 of 10 (permalink) Old 02-09-2019, 07:21 PM Thread Starter
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Quote:
Originally Posted by BA. View Post
You have a tough issue there for sure and there's certainly enough expertise here to get you through it.

Since you're in the middle of a potential fix, I just want to drop these 3 comments until we hear how your new wire run works out.

1. I am with Dave, due to personal experience, that you really should replace that Dimmer switch. They get faulty, cause grave issues, and they are cheap and easy to replace. Do it.

2. Bear in mind that you very well could have more than one issue. Don't let yourself get stuck on a single solution that solves everything.
3. Personally, I really really think you should find out where that mysterious 2nd small wire is going to from your battery post. It might be as simple as a home-run for a radio, or old switch someone installed, or hell, the key itself. People do weird things. If you can crimp or solder a wire (any monkey can!) than you might even consider just cutting it or removing it at the battery and you'll soon figure out what it was for if it serves any importance.




Cheers! Good Luck! Keep us up-to-date!

Thanks. I am within a process that includes replacing the dimmer; I simply have not got that far yet.

Regarding the 'second' wire; evidence so far points to a previous owner ran it to power the power seat he added (the car did not come with the power seat. It's obvious from looking at the install). The power seat worked before and does not now.

My car is a convertible. I've been told there is a 'circuit breaker' for the top motor located behind the driver's kick panel. I've also been told that power seats on convertibles run off the same breaker. All this has yet to be verified. That circuit is not in the '63 Shop Manual Supplement and I need to look at the '61 manual to see what that doc depicts. It was too cold today to go any farther on the car. My goal is to correct the power seat wiring too (once I verify how it should be). Until corrected, I'll leave it disconnected and 'blanked' off.

The car has a '383' sbc engine and I use a battery with lots of cranking amps. Another 'to do' is acquire a battery cable (2 gauge vice the OEM 6) w/o the fusible link. Goal is to have a better connection for the main power wire than wrapped around the clamp bolt. I like Big Dave's circuit breaker option a lot. I read his most recent post and need to acquire the proper rating.

The car is a 4 speed so I do not have to deal with neutral safety switch.

I'm ecstatic that I got the power back. The car runs now and everything but the power seat and the Dimmer are working.

Pete
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post #9 of 10 (permalink) Old 02-09-2019, 07:31 PM Thread Starter
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Quote:
Originally Posted by Big Dave View Post
12 guage copper multi-strand wire can handle 25 AMPs at 0-5 feet of length, though that factory wire is expected to carry 30 Amps (which is why I mentioned the factory undersized wires). A 12 gauge copper multi-strand wire used as a fuse (less than a half inch long) can handle 235 Amps before melting (why the factory though they couyld get away with under sizing wire)

Read this "NAPA know how" to size and identify automotive wires.

Know-How Notes: Automotive Wiring Guide - NAPA Know How Blog

Big Dave

So, if I am understanding the data; the circuit is SUPPOSED to be 30 amp. Would I be wrong in selecting the 35 amp breaker? Is that sufficient to protect w/o allowing annoying spurious tripping?

Thanks.

Pete
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post #10 of 10 (permalink) Old 02-20-2019, 11:22 AM Thread Starter
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Quote:
Originally Posted by BA. View Post
You have a tough issue there for sure and there's certainly enough expertise here to get you through it.

Since you're in the middle of a potential fix, I just want to drop these 3 comments until we hear how your new wire run works out.

1. I am with Dave, due to personal experience, that you really should replace that Dimmer switch. They get faulty, cause grave issues, and they are cheap and easy to replace. Do it.

2. Bear in mind that you very well could have more than one issue. Don't let yourself get stuck on a single solution that solves everything.
3. Personally, I really really think you should find out where that mysterious 2nd small wire is going to from your battery post. It might be as simple as a home-run for a radio, or old switch someone installed, or hell, the key itself. People do weird things. If you can crimp or solder a wire (any monkey can!) than you might even consider just cutting it or removing it at the battery and you'll soon figure out what it was for if it serves any importance.




Cheers! Good Luck! Keep us up-to-date!

Because you all asked for update:

I bought a custom 2 ga battery cable from:

https://www.batterycablesusa.com/2-g...les-2-awg.html

I had them add two 12 ga wires; one to replace the wire to the horn relay; and one if I wanted to retain the 'extra' wire that powered the power seats a previous owner added to the car. It was made up the next day and shipped. Wow, great response time. It arrived in two days; impressed with the workmanship. I installed it w/o connecting the wire to the power seats and the car started immediately and ran perfectly. Everything expect the power seats worked.

Yesterday I removed the driver's side kick panel and pulled up the carpet to get a look at the wiring to the convertible top, the power seats, and the dimmer switch.

The wiring for the top looked original and in very good shape. The circuit ( as far as I followed it) is in accordance with the wiring diagram from the '61 shop manual. There is a 40 amp (marked on the breaker) circuit breaker in that circuit. I intend to leave that as is. It always worked, is working, and I'm NOT going to fuss with it.

The wiring for the power seats was not run though the circuit breaker. It was 'added' (not surprisingly) and connected directly to the seat control circuit.

The dimmer switch look original. The wiring looks original and is run as shown in the documentation. I am going to replace the dimmer. I also decide to replace the 'guts' of the headlight switch as a precautionary measure. I bought a dimmer, the connectors to the dimmer, and the headlight switch from:

https://www.americanautowire.com

Part numbers 500042, 500286, 01995096.

As of today, I do not intend to re-wire the power seat. I bought a circuit breaker (American auto wire part 04850166) and will install that in the existing 'extra' 12 ga power line.

I'm waiting on the parts. When installed if everything works, I'm going to declare success (at least for now).

I'll update.

Pete
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