xrav22

Hi there and thanks in advance. I had the idea that if I changed the manual temp sensor(pass side) that my main fan would turn on at 214.
My mistake because I have my little loud aux fan kicking on at 214 now and I thought it was my main fan. My main fan still is at 227 of course it is controlled by ecm. Here is the question can I simply switch wires to the fan to have the manual control the main and the ecm can turn on the aux. How would I do that? Would it hurt anything? If I take the ground from the main and rerout it to the manual sensor, then take the manual sensor and run it to the ground to the ecm (where I cut the main ground) or should I just put a new toggle.
Edit. Mabey just switch respective plugs on the fans?

Cruisinfanatic

what's the matter leaving it stock?

don hall

We can only assume that you are trying to control a heating concern.
If so, what are the temps you are running? With proper air flow and
coolant flow, you should not overheat.

xrav22

My reason is that usually by the time I go to park it is always 227-230(with main fan on) degrees then after it goes up adding pressure to the old systems. It just seems to be better if i shut it off at 215 then it's not creaking and the temp really only goes up to 220 ish. I don't have the tools to program the eprom and I would like to just take some of the heat away in drive thrus ect.

c4cruiser

It sounds like you have a problem in the cooling system if the observed temps are that high. Starting the fan at a lower temp is doing nothing but masking the original problem. It's not a solution.

When was the last time a cooling system service was done? How old is the thermostat? Are the upper and lower radiator hoses in good condition? Is the cooling system full and no air pockets?

Is the radiator and A/C condenser clean with no buildup of dirt and debris?

Any or all of these things can result in higher than normal coolant temps.

playsdixie

you can get a two way switch at any parts store...16 bucks at ecklers...they are simple and work great. ..keeps my 85 190 in traffic in s florida...but....mine never ran that hot before I installed the switch.. you have to look for the issue.....the switch won't help as c4 cruiser says....

ejscarfo

I have the lower temp switch to turn my aux fan on at 190 in my 85. My main fan works and comes on at 227 but it hardly ever gets up that high, even idling in traffic. I'm also running a 180 thermostat. Make sure your radiator is clear and the coolant is flowing properly. You could have a water pump issue and not realize it either, just because it doesn't leak, doesn't mean its doing its job.

vetteoz

Simplest way, is to run a wire between the relay control terminals ( gr / wht wire ) on the relays
Switch will turn both fans on , if switch fails the ECM will still turn them both on at the higher temp .
There are other options , like you suggest but more wiring work

xrav22

Ok thanks for the opinions. I was driving today and it never really went over 210 in town
and it was 185 on the freeway. The little fan kicked on just as I was pulling in.
I have a 180 thermostat and just flushed the fluid with oil cooler hose change/ radiator drain. I am going to clean out any debris and clean the radiator and related items,cheers

Cruisinfanatic

best to take the radiator out because chances are it looks like this.