Question: Lower Temperature fan switch kits.

[bczee]

I am not sure how the Vette TPI and ECM works... but I know that many have put a HyperTech or other kits that include a new Fan Switch and sometimes a harness and some require a ECM change or chip.

On my 84 Z28 I used GM #3053190 (Delco 213-928 or Standard TS136) that has a on setting of 195 deg setting (may will require a different pig tail, as it is a button type and not a spade, Delco #PT308 pig tail will work)

For the C4, If I used the switch, would I also require making a ECM or Chip change ?

thanks..

 

[G Winter]

The fans are turned on by the ECM grounding the common terminal on the fan relay. If you want the fan-fans to turn on manually splice a wire to the common on the relay,connect to a switch in a handy place and ground the other side of the switch. The power to the relays is controlled by the ignition switch so even if you leave the fan switch on they turn off when you turn off the ignition.

Glenn

 

[jsinga]

I don't know if the year you have is different:
My 87, main fan controled by ECM
boost fan, out front controlled by temp switch in drivers side head.
I replaced the boost fan switch, it comes on at 190 now. Don't remember where I got the switch from.
It did help.
JS

 

[bczee]

What I know of most system and from what I have researched.. the 90+ is ECM controlled, but the pre-90's is not (?), 84-89 is switched and relay controlled. (guys correct me if I am wrong).

The Fans are not always controlled by the ECM. As in my 84 Z28.. it has a fan switch in the passenger side head and some relays to activate the fans (ECT in driver side head). From what I have read, my 88 (and I beleive your 87) should be setup this way also. I know my 99' LS1 does used the ECT for input into the ECM and does control the Fans via the relays.

The Engine Coolant Temp (ECT) switch feeds the ECM with engine temp input, for the L98... it should be on the front of the intake. This is the input that the ECM uses to control the fuel mixture and other engine operations (and gauge?)..

For the Fan setup.. there is a switch in the Right side head between cyl #6 & #8. When that switch hit 227deg (I believe that is the stock fan on temp is) then the switch closes the circuit to the fan relays and turns them on, once it drop below the setting.. it opens the circuit and the fan relays turn off the fans.

I could be wrong for the Vette..as I have not worked on the C4 very long and still learning.