Ok, I've had my '86 Trans Am for about 2 years and I'm still trying to figure something out!! My upper radiator hose looks like it's been cut (near the radiator) and there's been a piece of pipe it looks like clamped between the two pieces! There's also something welded into this pipe and it has two wires coming off of it!! Looks almost like a sensor of some sort but I can't figure out what for!! Both wires appear to be red (it was getting dark outside) and they have been run around in front of the radiator and into a wiring "loom" on the passenger side of the car near the vacuum canister and I can't follow them to see where they go!! At first I thought maybe it was a "homemade" temperature sending unit but I unhooked the wires from the factory temp sending unit and the temp gauge quit working so that's not what it's too! Anybody got any ideas what it might be??

 

Could be a homemade sender for turning on the electric cooling fan, if you are so equipped.

 

That would be a possibility but then I ask, why not just tap right into the wires at the fan instead of running them all the way around and into a wiring "loom"?? The "unit" is sitting in the upper radiator hose right next to the fan so I really don't think that's what it is!!

Also, I can't test to see if it's a homemade fan switch because I've already spliced into the wires at the fan and hooked up an adjustable fan switch from the local parts store!!

 

86,

It could be a fan control as others have speculated. The fan relay is near the area of the EVAP canister, so the wiring could have been to the relay. I did mine in a similar manner, but installed the sensor in the water outlet instead of the hose:



the reason the sensor wires wouldn't go directly to the fan motor is that the fan motor requires about 13A at 12VDC, and teh sensor might be good for about 500mA on a good day. The fan relay needs to be involved to avoid blasting the sensor on the first fan start. Your aftermarket fan control (DeRale or similar) has a relay as part of the control, so you can wire directly to the fan motor if you desire.

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Later,
Vader
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"What a Day..."
Adobe Acrobat Reader

 

Yep, that's about what it looks like Vader! That must be what it was for! My guess might be that the previous owner went to replace the fan switch and put teflon tape on the sensor which wouldn't let it ground properly to turn the fan on so they just bypassed it and hooked the one up at the radiator hose!! Doesn't matter much I guess since my adjustable one is hooked up now! Thanks all for your help!!