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Discussion Starter #1
Hello All and many thanks in advance for any input(s) that might be offered.

I've read multiple posts on this topic, attempted to troubleshoot things as has been suggested, but still no luck.

My '93 Spider with 35k miles was garaged for close to a year.

I had been driving it for a couple of weeks with no issues noted.

I got stuck in traffic on a hot day; the temp gauge climbed; the overheat light illuminated.

Managed to get home. Noted that the electric fans (the car has the two original ones installed and is completely stock) continued to run after the engine was shut off and the key was removed from the ignition.

I (literally) walked into the house, searched this forum, waited 20 minutes, got nervous (because the fans were still running), went out and disconnected the battery. The fans stopped.

The very next day I reconnected the battery and everything seemed normal for about the first 20 minutes. After that the engine temp started to climb, I headed home, the overheat light illuminated in the driveway, the fans did **not** come on (either with the key in the ignition or out).

I have been able to replicate the issue sitting in the drive. Start the car, wait ~15 - 20 minutes (while holding the RPM at ~2,000), the temp climbs and then the light illuminates. The fans do not come on.

I have:

Checked the firewall-mounted radiator reservoir: it is at the "Full" level, the water gets hot, there are no apparent bubbles to be seen in the fluid.

Felt both the upper and lower radiator hoses; both get hot to the touch.

Turned on the interior heater; it blows hot air.

Checked the fuses; they all (especially #5 and #6) appear to be intact.

Pulled the two leads from what I believe to be the temperature sensor (located on the engine-side, of the lower passenger side, of the radiator housing) and used a paperclip as a jumper between the two leads... there was a very small spark, but the fans did not come on.

Double and triple checked that the battery connectors have been securely reattached to the battery terminals.

My apologies for the long-winded ramble; but I'm not certain what I might have missed.

Many, and sincere, thanks,

sheldon
 

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sounds like the fan switch may be defective. i am not very familiar with the s4 but should be a fan switch in the radiator. unplug the two leads and jumper across with the ignition on. if the fan doesn't come on, fan motor or wiring is defective. if it does, switch is bad. second fan probably should only run with a/c
 

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But Mad North-Northwest
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Okay, something is very strange. The fan relay power feed has 12V with the ignition off, but the fan relay trigger gets 12V via switched power. So there should be NO WAY for the fans to run with the ignition off, and you should not get a spark when you jumper the radiator switch with the ignition off. That's what the wiring diagram says and I'm certain that's how my '91 is wired up.

Most likely thing I can think of is that the relay may have failed internally (they are semi-notorious for melting). Try pulling it and bench testing it: should be top row in the fusebox, second from the left. Has a fuse holder integrated in it.

If that's okay, I suppose it's possible that the car was either miswired from the factory (the original fan wiring diagram published by Alfa was *completely* wrong), or a PO messed up the wiring, or something else in the fusebox failed. In that case you'll need to get a multimeter and the wiring diagram and figure out what the heck is going on.

Anyway, good news is that it sure sounds like an electrical problem and not a more serious engine problem.
 

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Discussion Starter #4
Thanks guys! I appreciate the info.

Hadn't tried the a/c "On" configuration to check the second fan, but I will.

Also, please: I miscommunicated (my bad) about when it was that I saw the spark between the temperature sensor leads... the key was in the ignition, and it was turned to "On", but the engine was not running.

As for the fans running with the ignition "Off" and the keys removed... that was absolutely the case and not something that I had ever encountered before.

I'll visually check the fan relay tomorrow... but checking it with a Volt meter will require some self-educating (as to how to do that) on my part. Might just go ahead and order a replacement so as to definitively rule it out as a possible cause.

Many thanks again for the very prompt and informative replies!

s
 

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But Mad North-Northwest
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Also, please: I miscommunicated (my bad) about when it was that I saw the spark between the temperature sensor leads... the key was in the ignition, and it was turned to "On", but the engine was not running.
Okay, then the spark was normal but the fans should have come on. Again, that points to a relay problem, but you'll need to do some testing to verify. Or just see if it's melted...
 

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relay.

if you have A/C you can probably swop over the suspect fan relay(30A fused relay) for the A/C relay(10A fused relay, top row far right)

afaik they are identical apart from the fuse rating.

A/C is not as important as the radiator fans coming on when they should!
 

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I have seen a situation where a pinched or blocked hose to the overflow bottle allows coolant into the bottle but not return. Over time, the radiator runs low on coolant. Take the radiator cap off and add coolant until it comes up into the neck. If it takes a lot of water, you have found a clue. The fans in some cars continue to run after the key is off to complete cooling. If the water in the engine is very hot, the fan may run for some time.
 

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What doesn't make sense, unless I missed something, is if the fans are running, the engine should not overheat. So there seems to be some type of blockage in the hoses or coolant is not flowing as it should.
 

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Discussion Starter #10
Progress. Sorta. Seems that I now know where the problem might be, if not what it might be.

With spiderserie4's suggestion in mind, I set out to swap things out.

Not certain how I missed it previously, but when I pulled the fan relay out, it was very obviously burned/melted where the fuse plugged into the fuse holder. (Pics below.)

Note, please:
Before I removed anything, the fan fuse relay had a green fuse in it (no numeric markings), and the a/c fuse relay had a red fuse in it with "10" marked on it.

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So then I:

Pulled the a/c fuse relay (top row, far right) and plugged it into the slot where the fan fuse relay had been removed.

Started the car, drove it until it got warm; the temp never got above 175 dF during this time.

Parked in the driveway, set the RPM to ~2,500, and waited for the temp to climb.

At approximately one hash mark to the high-side of 175 I heard a "pop" and saw a quick flash of light.

The a/c fuse relay (which was (then) in the fan fuse relay spot) had smoke checked itself.

I turned the car off, popped the hood and saw nothing amiss.

Both fans spin freely.

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Any thoughts on what might be causing such a large load on the fan fuse relay would be appreciated.

And **many** thanks to all for helping me to troubleshoot things to this point,

sheldon
 

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But Mad North-Northwest
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Man, I hate being right all the time.

So the fan relay uses a 30A fuse. If you swapped the relay and used a 10A fuse then the fan load may be okay, it was just too much for the 10A fuse and popped it. Your rad switch closed at just the right temperature so it's apparently okay.

Two possibilities here:

1) The relay went bad...built up some oxidation or whatever, overheated, and melted on its own
2) You've either got a motor pulling too much current or a short in the fan wiring

My money is on (1) as (2) would've popped the original 30A fuse before it melted the relay.

To test for a short: with an ohmmeter, measure resistance to ground from each of the fusebox plugs where the 87 terminals of the relay plug into. This should be non-zero if you're not shorted.

Testing fan current is more of a challenge. Most ammeters only go up to 10A, and that's probably about what each of the fans pull. So you may blow the ammeter fuse if you try to measure fan current directly. I've got a 60A clamp-on meter but I'm not near Seattle. But like I said, given that the original 30A fuse didn't blow case (2) is less likely.
 

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But Mad North-Northwest
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If the water in the radiator is low, the engine will overheat even with the fan running. Happened to me.
Guys, I realize you're trying to help, but you're way off base. This problem has nothing to do with the coolant or coolant flow. Please read the problem description and testing results again.
 

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Discussion Starter #14
When you're right, you're right? :)

Sounds like getting a new relay might make a lot of sense.

Just did a Google search for the B047 relay. No luck finding it on any of the big name, local-to-Seattle auto parts store websites. And I'd prefer to not use eBay for something like this. Is Centerline International typically a good source, or might someone recommend someone else?

Many thanks for the help in zeroing in on this... I know it's not yet completely resolved... but it sure was nice to be able to tap into this brain trust vs. trying to find a shop that would even look at it.

I'll report back after I try a new relay (with the appropriately sized fuses).
 

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But Mad North-Northwest
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I think they may be NLA. You can get dual 87 relays that'll fit, but I haven't seen one with an inline fuse and the fuse is kind of important. Maybe try Alfa Parts Exchange for a used one, or maybe Centerline knows of a good cross reference.

In any case, I'm pretty sure the other relay is exactly the same. You just need to pull out the 10A relay and replace it with a 30A relay from your local auto parts store.
 

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If Vicks doesn't work out for you, then this german seller still has 8 s/h ones listed at
(about) 15$ each, plus a few bucks postage to US.
search ebay # 110935668170

that "pop" and melting shown in your photo would still worry me, though.
Even if you used the A/C relay with a 'too low' 10A fuse, I would expect the fuse to maybe go.....but to melt on you like that....?

Personally I'd drop the fuse box down, turn it over and check the connections feeding that fan relay.....
 

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I had the same fuse melting problem on my S4. I rewired the relay with a external fuse holder hoping that it would allow to fuse to remain cooler. It didn't help. What I did to fix the problem was to wire in two relays similar to the setup for headlight relays. One relay per fan with a inline fuse split the current load in half and no more melted relays with fuses in the fuse box.
 

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But Mad North-Northwest
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That "pop" and melting shown in your photo would still worry me, though.
Even if you used the A/C relay with a 'too low' 10A fuse, I would expect the fuse to maybe go.....but to melt on you like that....?
Dom, if I'm understanding right, the melting was the original relay. They do that sometimes, apparently. The pop was just the undersized 10A fuse in the second relay blowing.
 

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Dom, if I'm understanding right, the melting was the original relay. They do that sometimes, apparently. The pop was just the undersized 10A fuse in the second relay blowing.
Ah OK Tom, I think you're right, having reread it.

But I'd still be worried that any relay, yet alone a 'fused' relay, melts....something ain't quite right.

put it this way, mine has never melted!;)
 
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