Electrical head-scratcher - Alfa Romeo Bulletin Board & Forums

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  • 1 Post By papajam
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post #1 of 15 (permalink) Old 03-18-2017, 03:16 PM Thread Starter
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Electrical head-scratcher

Patient is a 1982 GTV6

Symptoms:

Passenger front marker and parking lamp not functional, bulbs good.

Driver's rear marker and parking lamps not functional, bulbs good.

Rear license plate bulbs not functional, bulbs good.

Driver's rear brake lamp functions when pedal is pressed (along with passenger rear brake lamp, LOL).

Instrument panel lights light up fine.

Grounds seem to be good in all positions where lights are not working.

The wiring diagram is hard for me to decipher, but it seems like all these lamps are in the same power circuit.

Fuses in 9 and 10 are good (via multimeter).

Can someone please give me some further troubleshooting steps? Thanks!
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post #2 of 15 (permalink) Old 03-19-2017, 02:22 AM
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The lamps in question are powered thru fuse #9. If the fuse checks good, then the fuse contacts may be dirty. Simply pull the fuse, clean the contacts with a pencil eraser and squeeze the contacts together a bit (to provide more tension on the fuse).
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Jim

Series 2 USA 1750 GTV (in Series 1 European clothing)
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post #3 of 15 (permalink) Old 03-19-2017, 04:44 AM
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Papajam's reply is very likely correct. Many of the fuses have an Alu element which corrodes at the contact points with the fuse holder giving rise to an impaired or zero connection. Fuses with brass elements are much better in this regard. Contact enhancing paste or spray can also help.
Check with your multimeter that 12v is present on both sides of the fuse (9) when the lights should be lit, also check 12v at the lampholders.
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post #4 of 15 (permalink) Old 03-19-2017, 03:08 PM Thread Starter
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Closing the circle (circuit):

The fuse was indeed the problem. It checked out as continuous. In place, it was firm in between the contacts. No joy. Replaced with a ceramic-bodied, brass-conductor fuse. All the mentioned lights now function.

The take-away: Just because a fuse conducts electricity enough to make the multimeter give a satisfied "beep!" does not mean the fuse is good enough to run an automotive circuit.
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Last edited by nemesis; 03-19-2017 at 03:41 PM.
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post #5 of 15 (permalink) Old 03-19-2017, 10:00 PM
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I am convinced from first hand experience, that if all Alfa owners pulled those corroded overheated aluminum fuses tomorrow, cleaned the contact fingers and replaced them with copper and/or brass fuses, these kind of posts would drop by 75%.
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post #6 of 15 (permalink) Old 03-22-2017, 09:18 AM Thread Starter
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Quote:
Originally Posted by alfaloco View Post
I am convinced from first hand experience, that if all Alfa owners pulled those corroded overheated aluminum fuses tomorrow, cleaned the contact fingers and replaced them with copper and/or brass fuses, these kind of posts would drop by 75%.
This is the truth. Since I didn't have enough of the right kind of fuses to do this job, I didn't do it when I posted my fix. But I immediately ordered enough to get it done and have plenty left over. I will do exactly as you suggest, and also use a squirt of Deoxit D5 on each contact. I consider this preventative maintenance, and I might add it to my 60k-mile schedule. Every 60k, do this exact thing. Cheap, easy. And since I daily this car, the next 60k isn't that far off. Four years, really.
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post #7 of 15 (permalink) Old 03-22-2017, 09:26 AM
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Since we did the electrical PM work on Mike's car back in the fall of 2014, he has had ZERO electrical weird stuff happen with his GTV 6. Nothing. All the aluminum fuses that came with the car... we pitched in the trash.
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alfaloco
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post #8 of 15 (permalink) Old 03-22-2017, 12:24 PM
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Of all of the problems people have with their Alfas, most are electrical in nature, usually caused by dirty/tarnished/corroded connections in the wires, switches, and fuse installations. My original Alfa, the 64 Giulia Sprint GT, always had problems because the fuse box was in the engine bay, not inside the cabin. the worst case of failures I've run across. Those fuses usually got very filthy and were always giving problems. Nothing like having the headlights go out because of dirty fuses. I finally wrapped the box in plastic, and that helped a lot.

For the later Alfas, seems that many of the wiring connections, esp in the engine bay, were subject to tarnishing/corrosion/dirtiness, and thus not conducting, sometimes irritatingly intermittent, so much that Alfa payed for the cleaning and protection labor by mechanics in many cases and models. And we are all familar with the switches for the 164 seats and windows, the switches being of a certain quality/design, that they were more susceptible to failure than those of most other marks it has seemed.
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89 Milano (wife's daily driver since 1989, Shankle Sport)
91 164S (my daily driver since 1994)
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72 Morgan 27 (water time since 1976)

previously owned since 1964:

62 Morris MiniMinor 850, 67 Austin 1275 Cooper S (Downton 3/4 race), 64 Giulia Sprint GT (1st red one made), 72 Fiat 128 Sedan, 75 Alfetta Sedan, 78 Alfetta Sedan, 78 GTV, 81 GTV6, 86 GTV6

Last edited by Del; 03-22-2017 at 12:54 PM.
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post #9 of 15 (permalink) Old 03-22-2017, 01:11 PM
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Aluminum and brass (the fuse holder contacts!!) are known galvanic reactors - they corrode in contact with each other!
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50 years from now - how are we going to restore a "classic" microprocessor based modern car?? Alfas - 1980 Spider, 1987 Milano, 1976 Spider
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post #10 of 15 (permalink) Old 03-22-2017, 01:24 PM
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Wow! So based on the chart posted by Bruce, aluminum is the worst fuse link material you can use in contact with brass or copper. Nuff said, right? This info ought to be plastered all over this forum AND the tech forum, frankly! Or maybe stickies...

Señores administrators???
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post #11 of 15 (permalink) Old 03-26-2017, 07:03 AM
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I found out the hard way. Use copper or brass fuses. Those aluminum ones from the parts store are no good.
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post #12 of 15 (permalink) Old 03-26-2017, 09:58 AM
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I found out the hard way. Use copper or brass fuses. Those aluminum ones from the parts store are no good.
Yup-- that's why you often see the links warped on the aluminum fuses. It's from the heat, and the heat comes from resistance building on the ends, from corrosion!
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post #13 of 15 (permalink) Old 03-26-2017, 11:13 AM
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Aluminum house wiring was also a disaster, with more than a few houses catching fire from the over heating connections. Friend of mine had that in his new house, at the time, and had more than one blackened plug socket box. Had to go through the house, take each box apart, and apply the special goop to prevent that resistance buildup and heat.

I suppose that goop would work if you couldn't find the good fuses, not that I'm suggesting that.

Del

Seattle

89 Milano (wife's daily driver since 1989, Shankle Sport)
91 164S (my daily driver since 1994)
94 164LS (~Q) (trip Alfa since 2000)
72 Morgan 27 (water time since 1976)

previously owned since 1964:

62 Morris MiniMinor 850, 67 Austin 1275 Cooper S (Downton 3/4 race), 64 Giulia Sprint GT (1st red one made), 72 Fiat 128 Sedan, 75 Alfetta Sedan, 78 Alfetta Sedan, 78 GTV, 81 GTV6, 86 GTV6
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post #14 of 15 (permalink) Old 03-31-2017, 10:22 AM Thread Starter
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Well, that was truly interesting.

Digging into the fusebox led to some serious questions about the mental state of the previous owner(s). Hey, if a circuit is blowing fuses, most folks find where the high draw is. Not these guys - the solution was to put in a fuse of a higher current rating. I had two circuits where the stated value for the fuse was 8A and the fuse in those circuits was 25A. Uhhh, wut? Cleaned the contacts, put in copper or brass fuses of the correct rating, sprayed it all down with Deoxit D5, and went for a drive to test everything. Well, look at that - all the lights are brighter. The windows wind faster. The wipers run slightly faster (still need to relay and clean up that wiper motor). This was a very simple fix that I did in about a half hour. The thing that took the longest was cleaning the contacts in the fusebox with a brass wire wheel chucked into a Dremel tool. We'll see if there are circuits that really do actually have a high draw or not. If they do, we'll attack them one at a time.

And not just throw a bigger fuse at them. [eyeroll]
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post #15 of 15 (permalink) Old 03-31-2017, 10:38 AM
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"I had two circuits where the stated value for the fuse was 8A and the fuse in those circuits was 25A."

Oh Oh... if that's the case, then you really ought to be on the lookout for burnt wiring/melted insulation on those circuits. That comes from my unfortunate past experience years back with old British cars, where 35 amp fuses were the norm. Couple that with the old crap Lucas apparatus, and it's no wonder Jags, TRs, etc. ignited and burned to a crisp.

It wouldn't surprise me if you had a bit of wiring damage in there. I share your opinion of PO's who butcher wiring instead of troubleshooting the issues.
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alfaloco
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