ejscarfo

Everything works as it should in my 85 T/A. The fan comes on around 230 and it hasn't overheated in traffic, so far. However, I was wondering what controls the fan. Is it a sensor in the head or the ECM?

In my C4, I have 2 fans, a main and an aux. The ECM controls the main (the one facing the engine) and a sensor controls the aux (in front of the radiator). The sensor for the aux has been switched out so it comes on at 195 degrees and it works great. The main fan, which is to come on at 230 or with the A/C, hardly ever comes on, even on 95 degree summer days.

So, my question is this, can I modify the fan in my T/A to come on earlier?

Ozz1967

iTrader: (4)

The single electric fan runs of a switch in the passenger side head, just forward of the dipstick. You can change this out for ones that co e on at different temps if you'd like. Additionally, the fan will come on when the AC is engaged, which can help as a troubleshooting tool if you fan stops coming on when it should.

ejscarfo

The fan works with the A/C and comes on at 230 or so without the A/C. I'd like it to come on at around 195 which is why I asked. Do you know the part number of one that will work at the lower temp?

ricci66

if u run a jumper from the primary cooling fan relay to the secondary cooling fan relay .....both will come on together and go off when temp drops , terminal ...F ....on the relay is the switched grounded wire that allows the relay to pull in and allow power to the fan.

ejscarfo

My T/A only has the one fan so that's not gonna work. My C4 has two fans. I wanted to just replace the sending switch to one that makes the fan come on sooner.

antman89iroc

Check Summit. They have a lot of different thermal switches you can chose from. One suggestion is to not use a TS with a setting lower than the thermostat installed. If you do the fans will always run once it gets hotter than the TS setting. For example, I have a 195' thermostat. I chose a TS with a 205 on-195 off from Vintage air PN 11205VUR. About $40. It requires a different connector on the wire and a threaded adaptor but that's not a big deal to me. There are others but most are designed for a 160 or 180' tstat.

ejscarfo

I checked Summit for the part numbers I found in an old forum post here, all were discontinued. I will look up the PN for the Vintage Air one tho and see what I find. I thought of using the same kit I used on my Corvette, the heads and fittings are basically the same and since it doesn't run to the ECM, it should work.

The car doesn't have a thermostat, if it does, it's stuck open. The water starts to flow in the radiator as soon as you start the car, cold. I was going to add a 180 thermostat with the 195 switch. Would that work? That's what is in my Corvette and it works like a charm.

Ozz1967

iTrader: (4)

If you do a search here on this board, there are several posts that i"ve seen with the different switches. The one I run comes on at 215. IF you go to Jet Performance Products, they have one that comes on at 195, turns off at 180. I found that my fan was running all the time with that one installed.