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1980 Brat - Radiator switch wiring.

Featured Replies

All,

 

When I got the Squirrel the fan was hot-wired to the wiper motor.  I am assuming that the switch was bad.

 

That being said I replaced the switch and have her running now.  But I cannot find a lead for the switch.  The fan has tow wires and those are connected to the harness.

 

Can someone with a gen 1 please take some pics and explain how their radiator switch is wired.  I would greatly appreciate it.

 

Thanks.

Jon

The radiator should be grounded to the core support at the top. This serves as the ground for the thermoswitch. The thermoswitch is a single spade. If you short that wire to ground the fan should come on if the circuit is working properly.

  • Author

Yes, understood.  I have the radiator grounded to the core but nothing coming off the switch.  This is what I am after.  My switch has no wiring to it.

 

Thanks

the switch should go to the negative wire coming from the fan. The power is coming from a hard wired cource that is direct to a battery source as to stay on even when you shut the engine off so that she cools off while you wait.

I have my switch re-wired on the 78 brat with a relay and fusible link straight to the battery as the fan tends to  pull alot of amps from the ancient charging system.

  • Author

K, either I am not getting this or I am just stumped.

 

The the fan has two wires coming from it.  The harness up to the fan has two wires coming from it.  Unless I am losing it I assumed that these plugged in together.  The leads off both are offset and seem to be what was intended but I cannot say.

 

So you are saying I need to wire the switch to the negative off the fan and then run a hot to the other from the battery.  That would remove the two wires that are connected to the fan right now.  What are those two wires for then?

Edited by O.C.D.

should be a single round pin yellow or blue wire about 4-6 inch from switch breaking out of main harness

on my 78 it had one wire from the switch to the fan...maybe re-wired from previose  owner but not sure. It had a manual fan on a pulley and the electric only came on when hot.

on my 79 it had 2 coming off the switch. one to the fan and te other to the harness. there was no manual fan and the electric fan was always on while the motor was running and i think the switch was a back up to keep it on when hot after shutting off the motor.

reguardless i re wired all my fans. if you want it as a backup all you need is a fused non switched Battery power source ( I go sraight to the battery) and the radiator switch is the ground. if you want it to come on when the engine is running you must find a ground source that is switched possibly one of the wires you are looking at. or run a relay from the ignition to switch a groud source so that the fan runs while the ignition is on and stays on after shutting down if hot.

I would run a test light to the wires and see if one of them is a switched ground first.

my guess is the wires are fried and thats why some knucklehead wired it to the wiper motor.

Unfotunately i have yet to see an un-tampered wire harness.

Hopefully someone here has.

I just started thinking that i did not re-wire the 78..i just ran an electric to eliminate the manual one when the bearings fried( Melted the fan off the mountf romk the friction of the belt).. anyway i just checked the wires and the fan has a blue and a black coming from the wire harness directly under the radiator and the switch wire is a solo black with a female round post connector comin from the same harness as it branches out to the passenger side headlight. i does this right under the battery platform.

Hope this helps.

  • Author

I just started thinking that i did not re-wire the 78..i just ran an electric to eliminate the manual one when the bearings fried( Melted the fan off the mountf romk the friction of the belt).. anyway i just checked the wires and the fan has a blue and a black coming from the wire harness directly under the radiator and the switch wire is a solo black with a female round post connector comin from the same harness as it branches out to the passenger side headlight. i does this right under the battery platform.

Hope this helps.

 

Thank you I will check.  I have looked for this thinking it should be about there location wise but nothing.

 

And you are right, these harnesses always seem hacked.

On most i use the fan switch to turn on realy that controls fans the rad switch could not handle to mutch load make a realy take the load and is very easy to ground switch realy I like the silver subaru relays 84-99 generic four pin

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