Paul85TA

can somebody post a picture of which harness the radiator fan motor wiring comes from
My car was butchered years before i got it, then eventually had a separate controller installed right before i bought it. that just quit working so im looking to fix it right. the problem is i cannot even find the positive wire for the fan itself(clipped at the end of the radiator and respliced into separate controller)

car details:
1985 trans am 305 tpi vin f
Radiator fan relay is located on passenger side of radiator
Switch is on passenger side head
Both of these being replaced since the sensor / pigtail were broken.
Wires from fan run to drivers side of radiator. this is where i need pictures.
Ground goes to core support, positive = ??
Also
If anyone could post the CORRECT diagram for an 85 with tuned port. that would be appreciated
from what ive seen most of the others have a black/red wire coming from the relay. Im not sure if this is the same

Ron U.S.M.C.

Maybe this will help some.


http://www.austinthirdgen.org/?pid=19


I don't see a TPI in 85 but there is one in 86 .

Should be identical.

Is the relay intact with the wiring as described in the diagram.(color) If so you should be able to run a wire to the Positive/hot "going in" to the fan like this. Pin #87.
The switch in the head for my car is located at the end of the low amperage #86 grounded pin.

You can put an adjustable temp controlled switch there if you want.
Don't get the polarity mixed up. Most fans will spin either way. Push or pull

mantaguy

iTrader: (5)

This is for a 86 TPI 305.they are the same.

Ozz1967

iTrader: (4)

The fan "negative" should go to the relay. Also, your relay isn't up by the fireall? Hmm....I thought all single fan set ups for Firebirds had the relay by the firewall. Interesting.

Passenger head swtich controls the "temp" the fan operates. Drivers side head switch is the temp gauge sender in the car.

There is also a sensor on your intake manifold that tells the ECM how hot it is, helps with TPS/O2 sensor readings/settings while driving.

mantaguy

iTrader: (5)

Paul85TA

Previous owner ran the radiator fan wires to the wrong side to make it easier to hook up an aftermarket controller. after doing some digging around on the passenger side i found two wires hanging outfor it

kenbob

So I have a 1986 and the 85/86 don't have a passenger side fan switch just a temp sensor and sender the ecm reads temperature then grounds the green and white wire

John in RI

iTrader: (167)

85 and 86 did have a head-mounted fan switch,.....IF it was factory Carb,

Here is the CARB fan wiring for the 85:



Here is the TPI fan wiring for the 85:


Pretty sure that 85 and 86 TPI were factory wired the same way............

kenbob

They do have a head mounted switch but 85-86 coolant temp switch is also the gauge sending unit it grounds through the ecm but it only turns on when the gauge reads almost 3/4 hot. If you run an auxiliary coolant temp switch and tap into the fan relay with two wires one to the green and white wire and the other to ground. Mine has an adjustable **** and if it fails the ecm will still kick the fan on at 238 degrees

kenbob

So the head mounted switch is in the drivers side nothing on the passenger side that's for dual fans

kenbob

John in RI

iTrader: (167)

Incorrect. Every (V8) has a drivers side Head mounted sending unit for the temp gauge,..... It's a 1 wire connector.

Fixxed.

kenbob

Are you guys not reading the part about 85-86 TPI only! has three temp sensors one cold start switch, one ecm coolant temp sensor and one driver side coolant temp sensor/switch green wire TPI doesn't have a passenger side temp switch. I don't bother with carburetors anymore especially computer controlled carbs or TBI.

John in RI

iTrader: (167)

Just correcting the misinformation; you might not need to deal with a pass side cooling fan temp switch in the pass side head with an 85 or 86 TPI,.... but many other members here do still own a Carb - or a later year TBI - Thirdgen so both 85 designs were described. You bumped a 4 year old thread and I replied your info with factory diagrams - agreeing with you. ( 1 sensor for fan, 1 sensor for gauge - that's it) Strangely; You followed up my post with some incorrect info that needed to be corrected that that in another 5 years from now the next guy to read the this thread has the correct info about his 85 TPI.

This is not correct. There is only 1 sending unit that passes a signal to the temp gauge; and that is the ONLY function of that sensor. It's factory located in the drivers side head of every V8 Thirdgen. If your TEMP gauge isn't reading till it's 3/4 hot,... then it's time to replace your defective gauge or that defective sending unit.

No; Please revisit post #8. You will notice it contains the wiring diagram of the 1985 TPI Cooling Fan system. ( ECM temp sensor is located next to the Cold Start on the intake; 1 sensor - not 3.) It also contains the 1985 Carbureted electric fan Cooling Fan system schematic to help explain / reduce any possible confusion about what electric fan system uses a pass side head mounted switch; and what systems use the ECM for fan control in 1985 (or 86 / 87 TPI Single fan) V8 Thirdgens. There are other variables that can turn on an electric fan, such as AC line pressure (TPI) and the AC controller head (CARB), but they are not primary switches and can't be counted as any type of sending unit.