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mmelton
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Grounds? Hot Fuses?

Post by mmelton »

So I had the fuse box open on this new-to-me '86 GTV6 that had sat for a year under the white oaks (we have around 3,000 development miles on it now). I was tracing a driver's window lift problem (Alfa Stan said it was probably corrosion on the relay prongs--and he was right, as usual) but I noticed, on starting the car, blue fire jumping around fuses 4 (door mirrors, courtesy light, stop light, clock, ignition switch seat light, radio, door buzzer, hazard flashers, fusebox light) and 5 (elctronic injection). Cleaned up the fuse holder/contacts and started it up (no more jumping blue fire), but noticed that 4 and 5 fuses (both 8 amp) got hot when the engine is running. And when the fan ran no. 3 fuse (a 16 amp) got OWW! DAMMIT! BURNED MY FINGER hot.

Removed all the fuses and went after the whole array of fuse holders/contacts with a Dremel tool. Cleaned them up/down and in/out til the little holder rims shined, renewed several dodgy-looking fuses (and changed several 25 amp back to proper 8 amp), then went after the grounds. Scraped/ground/filed off paint (or rust where that had already been done) at ground points, cleaned the ground wire contacts til they shined on the little two-ground point (small screw) just in front of the passenger side firewall, the three-ground point (13mm bolt, I believe) forward beneath the air filter pan, its companion four-ground point forward on the driver's side, the big cable that grounds engine block to body just under the leading edge of the hood, and the battery ground in the trunk. I expect there are others foward that I've missed (including the computer ground: Where is it?). Then, with no more blue fire and the car running well, made a 90-mile midnight test run, and found nos. 4 and 5 still running hot to the touch, no. 3 cool (no fan running), and nos. 13 and 14 (high beam r. and l.) warm as well. All that cleaning had resolved nothing.

Then, checked my '85 GTV6 (a little over 30,000 development miles since rescuing her from abandonment last year) and found EXACTLY THE SAME THING.

What's going on? I initially assumed I had a developing problem with the '86 and thought this post would be asking: "What am I missing? Where's my problem?" But now, I wonder: Is this electrical behavior standard on our Alfas? In all these years and all these miles, I've never felt around my fuses to see if they're running hot. Did my Milano do this for 200,000 miles? Do all GTV6s? How 'bout our Spiders? Is this normal?

Can anybody make sense of this for me?[/quote]
Mel Melton
'85 GTV6 (Old Red)
'86 GTV6 (New Red)
'84, '88 Spiders
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Murray
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Post by Murray »

Mel I can offer my comments as I am in the fuse business.
Test standards (CSA & UL) for fuses allow for a temperature rise of 75oC ( 1670F) over ambient temperature at full load.In other words fuses operating close to their capacity can be surprisingly hot and this is normal and acceptable.If it's any consolation #3 on my 86 GTV6 has run hot enough over the years to deform the plastic cover.The upside of this is that if ever there is a fault in the circuit the fuse will react very rapidly and prevent a fire.The downside is that it is very important to maintain the quality of the contacts (which you have done) because the heat accelerates oxidation of the surfaces and causes the contact resistance to rise creating more heat etc....
1986-GTV6
1989-75 Twinspark very sadly sold-remarkable sedan !
2014 Audi Q5 3.0l TDI - torque MONSTER
David
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Post by David »

Mel,

I had a similar problem when I first purchased my 84 GTV6 with # 3 fuse getting hot and blowing. Corrosion of the fuse holder ends was also a problem and fitting a higher amp fuse sometimes resulted in blue sparks and melting the brass ends off the fuse.
After a lot of testing and with the benefit of a spare wiring harness and fuse box, I traced the problem to an incorrect relay on the fuse box. While they look the same they switch on different terminals. The wrong relay was in fact allowing full load to run through the fuse. With the correct relay in place the fuse now does not even get warm.

David
1985 GTV6 3.0 Zender Body Kit - Red
mmelton
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Post by mmelton »

Many thanks, Murray and David. You've eased my mind on this fuse annomoly (sp? I've become dependant on a spell checker).

My owners manual verbiage suggests that the troublesome no. 3 is a fan cooling the A/C. But I think there's just the one pair of fans that operate to cool both radiator and A/C condensor. Yes? I'm thinking of taking New Red on a 2,000 mile swing through Memphis, the Ozarks, then down thru New Orleans and back to west Georgia in a few weeks, and had visions of that cooling fan circuit immolating the car (already had that experience with my Milano. The old dry leaves on the relay trick. Came from letting the car sit for too long while driving the Spiders).

Looks like fuse oxidaton check needs to become one of the standard maintenance routines.

David, your commentary on wrong relays leads right down the avenue of my suspicions. I thought it might be too narrow a guage wire. Mismatched relays sounds more like it. Which leads to the question: How do I insure that I've got the right relays? (guess I won't be pulling those out of my old Milano and casually using them as spares). Are they marked with identifying codes? Has anybody seen (on this site or Oldebottles or GTV6.org or anywhere else) a list or chart of these relays with their markings? Can the current relays be checked for proper performance with a VoM or any similar instrument? Any more information would be most welcomed.

Thanks again. I'll be driving (another 90-mile jaunt on great Georgia roads is on tap in an hour or two) with an easy mind.

Thanks again,

Mel
Mel Melton
'85 GTV6 (Old Red)
'86 GTV6 (New Red)
'84, '88 Spiders
David
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Post by David »

Mel,

Further to my earlier post, a couple of things that may help you. My previous comment that relays are all different is not quite correct. There are only a few types. This may help diagnose your problem.

Standard operation is for the RH fan to come on when the AC is turned on regardless of radiator temp. Both fans come on when the radiator temp switch is activated. It is common practice for AC repairers to wire up both fans to come on with the AC.

My observation is relays generally have 5 pins with 3 versions of pin 87 and are usually numbered as follows:

Pin 30 – Load power in.
Pin 86 – Relay "on" switch.
Pin 85 – Ground.
Pin 87 - Load power out when relay is on. Where there are two pin 87’s they are connected, ie two power outputs. Let’s call this Type 87.
Pin 87a – Load power out when relay is off but load power off when relay is switched on. (Not connected to Pin 87). Type 87a
Pin 87b – Load power out when relay is switched on. (Not connected to pin 87 but two power outputs). Type 87b.

I have a late ‘84 and a late ‘85 GTV6 and the fuse box wiring seems basically the same. Fuse # 3 protects the RH fan and the AC compressor circuit. The LH fan is not fused. The relay numbers 1C, 3C, 5C, 4D. etc, don’t seem to mean anything as I have the same “types” with different numbers.

GTV6 Relays are as follows:

LH Fan – Relay # 4 - Can be any type as second pin 87 or 87a or 87b not connected
RH Fan – Relay # 5 - Must be a type 87 as one pin powers the RH fan if the radiator temp switch is activated and the other pin gets power for the RH fan from the AC relay if activated regardless of radiator temperature.
AC – Relay # 6 – Must be type 87b as one pin powers the RH fan and the other pin powers the AC compressor.

My problem was that Relay # 6 had a type 87 relay installed which meant the AC compressor was turned on (but not the AC inside the car) whenever the radiator temp switch came on. This seemed to be what overheated # 3 fuse and also explained the erratic nature of the problem.

Now the funny part of this saga is, I recently had the AC re-gassed in my other GTV6 and when checking relays this morning to put this post together, I noticed signs of overheating on fuse #3 and guess what? wrong type of relay in # 6. By shorting the fan temp switch to switch on the fans, the AC compressor clutch was locked on but the AC was turned off inside the car. Fuse #3 was getting very hot. Swapped the relay to a type 87b and fuse # 3 just warm.

Sorry if this post is a little drawn out but after spending considerable time trying to solve this issue it might be a solution to the overheating #3 fuse.

Mel, I’d be interested to know what relay you have in #6.

David
1985 GTV6 3.0 Zender Body Kit - Red
mmelton
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Relays

Post by mmelton »

Hey, David:

Many thanks for this. Couldn't ask for better. I've printed it, and will spend some time with the fuse box and the relays and my guru, Alfa Stan, trying to digest this...as soon as I get the time. Going on the road for a fast research trip (not in New Red--its cabin is just too hot to be doing 2,000 miles through Dixie in August), so it'll be awhile.

Here's a small question. I've replaced by '85's fans with my big Milano fan (an often-recommended) ploy, and probably will swap it into my '86. I think we hooked it to the right (A/C) side. Any warnings or recommendations about this?

Thanks again.

Mel
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'85 GTV6 (Old Red)
'86 GTV6 (New Red)
'84, '88 Spiders
David
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Post by David »

Mel,

The RH fan plug is the one to use for a single fan. Just something to remember, the fan runs the whole time the AC is on so even at 70MPH that fan is still running and probably not really doing anything.

BTW, I tested relays 1,2,3 & 7 and they are all "type" 87. The relays are easy to check. Hook up a battery to pin 86 and 85 and you will hear the relay click on. Some relays do have current directional diodes across the switching pins but none of the original AR relays seem to have this. Then with a multimeter, check pin 30 against the 87, 87a & 87b pins.

David
1985 GTV6 3.0 Zender Body Kit - Red
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