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Discussion Starter · #1 · (Edited)
I am rewrapping some wiring and after pulling off all the old tape I noticed this. Two R/W wires joined together. One goes to the radiator fan connector and the other goes to the radiator thermoswitch. Someone had already done some work in this area, so this appeared to me to be some kind of hack or mistake. But then looking at the wiring diagrams, I'm starting to wonder if it's factory correct. Anyone know? Also noticed the factory put solid plastic sheathing material in two places that I never noticed before, then covered those in tape. I assume that was to deal with heat or something.

Here's the wiring in the car:

Electrical wiring Cable Electrical supply Wire Electronic device



And then as you can see there is a junction of two R/W wires in the diagram, so this may be factory correct and I should leave it alone. The symptom I was having was the rad fan would come on sometimes many minutes after the car was turned off, and would only run for a brief few seconds, then turn off or turn on and then turn off so quickly the fan hadn't even got up to speed yet. So something funky is going on. Might be the thermoswitch itself, or the wiring and this curiosity is what I found.

Rectangle Circuit component Schematic Font Slope



Here are the sheaths. I don't think these are used anywhere else on the car, at least I've never seen them used anywhere.

Musical instrument accessory Automotive exterior Auto part Musical instrument Bumper


Another oddity is this junction of two R/B wires to a single R/B wire. Not sure if that's factory or not.

Electrician Electrical wiring Finger Circuit component Electricity
 

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I’m not 100% sure about the Corrado, but factory line splices were very prevalent in older vehicles, especially those that are hand-built. Based on looking at the wiring, is your engine code AAA? I do see the line splice, so it may be OEM correct. I would look into the thermoswitch as the culprit.
 

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I've seen splices like that on my SLC, I'm fairly certain they are factory. I saw them when I pulled the ABS, A/C, and electric seatbelt wiring. Couldn't tell you more specifically than that.

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Discussion Starter · #4 ·
Ok cool, I'll leave it as is. Likely the switch needs swapping. I cleaned out all the 30 years of grime underneath the wiring harness beneath the battery as well. Amazing how dirt somehow finds it's way under the thick wiring bundles under the battery. It gave me another 1/2 of clearance to lay down the harness...lol.
 

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That’s a factory wire union.

What you describe with the fan coming on is the afterrun functionality. On the g60 there is a thermo switch between the valve cover and intake manifold to trigger the afterrun. If you want to extend that afterrun period you could buy a hella timed relay to force it to run for x period of time after the ground switch coils off.
 

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Discussion Starter · #6 ·
That’s a factory wire union.
What you describe with the fan coming on is the afterrun functionality.
Yes, I'm familiar with the afterrun feature. But the fan should either stay on after turning the engine off or come on pretty much instantly and stay on until the temperature drops. With this car, the fan is coming on 5 minutes after the car has been off on a cool day, and then turning back off in a couple of seconds, often before the fan has even got up to speed which is not correct behavior. My guess is it's the thermoswitch, since they can be problematic, especially aftermarket ones, but before installing a new one I wanted to check on the wiring for all that since I could tell someone had been in there before. I just ended up cleaning the battery area and retaping all the wiring, but noticed this union, which I hadn't seen anywhere else on the car before. All the wiring seemed ok, other than the ancient cloth tape so I just rewrapped it all (using Eric O's trick) and organized it a bit better.
 

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Discussion Starter · #7 ·
I filmed the radiator fan weirdness today after shutting the engine off. My car sounds possessed! You can hear it turn on then off very quickly at around 3:27. I assume it's a bad thermoswitch but I guess could be a sensor or the FCM too.

 

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On hot days after shutting the engine off, my radiator fans pretty much do the same thing (after running a few minutes to cool the engine). I think it is due to the aux water pump circulating hotter coolant into the radiator. If yours is doing this on a cool day (or cooler engine temps) then I'd suspect either the radiator fan switch or the after-run sensor are bad. You will have to drain some coolant to replace the switch & sensor. Get some hose pinch pliers to pinch the radiator hoses which will limit the amount of coolant drained.
 

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Discussion Starter · #9 ·
On hot days after shutting the engine off, my radiator fans pretty much do the same thing (after running a few minutes to cool the engine). I think it is due to the aux water pump circulating hotter coolant into the radiator. If yours is doing this on a cool day (or cooler engine temps) then I'd suspect either the radiator fan switch or the after-run sensor are bad. You will have to drain some coolant to replace the switch & sensor. Get some hose pinch pliers to pinch the radiator hoses which will limit the amount of coolant drained.
Interesting. My other Corrado never does this, just turns the fans on for a while and then off. I think the only difference between the two is that one has an OEM switch and the other has a likely Chinese aftermarket switch. You don't want that sensor to change temperature too rapidly and cycle the fan on/off constantly. HVAC systems use a deadband to avoid bouncing between heat and cool set points, so I wonder if the some switches change temperature too rapidly.

I usually just do a quick swap over with the thermoswitch losing a cup of antifreeze or so with the jack lifting the driver's side to use gravity to help lose less. I was waiting for a point where I might need to drain it for something else, but it hasn't required it. I don't like pinching old hoses, it seems like tempting fate to me. I don't even look at hoses too long :)
 
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