This is on my '88 Iroc-z 350 TPI. The secondary fan is on the drivers side and the primary fan is on the passanger side correct Ok I grounded the secondary fan relay which is located on the pressure cap side of the radiator Because the guy who had it before me had a toggle switch in the car to turn it on (got tired of turning switch on and fogetting to turn it off when I turn the car off and the wiring was so screwed up it wasnt funny). Now the secondary fan comes on with the key great cooler temps. Next my primary fan comes on as soon as I turn my key on also, the temp. switch or relay is not grounded but I guess the guy that owned the car before me ran a wire from a tan, or light brown wire on the relay to the power wire on the primary fan.WTF. I have read on this board somewhere that I could ground the temp switch to get the primary fan to come on but when I do this I can here the relay click and fan does not come on ( this is with the bypass or what ever the hell it is that goes from the tan wire on the relay to the power wire of the primary fan disconnected). When I hook the wire back up the fan comes on with the key and stays on until I turn the key off (this is with or without the temp. switch grounded).:lala: :lala:

 

The primary fan is the driver side fan. Secondary is pass side. That IS the stock setup. The ECM controls the primary relay which is the one below the rad cap, the fan switch on the pass side block turns on the sec relay without assistance from the ECM. Sec fan is also controlled by an AC press switch. If the sec fan circuit is grounded to turn it on BOTH fans will run, as the ECM defaults. This is why I hate modified setups. it is not needed if the cooling system performs properly. There are wiring diagrams here on the site if you don't have a wiring diagram handy. Restore all wiring to factory to start with. Replace the relays with NAPA #AR-279. They are a redesigned version of the original and are more reliable. On a stock setup the primary(driver) fan will come on either when the engine reaches about 220 degrees or when the AC is turned on. The secondary fan comes on at about 238 degrees. Disregard all the garbage you read about wiring in switches, lowering fan turn on and the like. The engineers designed the fan cycling for a reason. Putting in a lower sec fan switch not only cycles the fan more often but will turn on BOTH fans. The electrical load on the alternator is temendous, don't do it. Everybody seems to think they know more than the design engineers but after 20+ years of working on auto electronics as well as other areas trust me when I say it's that way for a reason. If you need more help PM me, and I'll walk you through it.

 

Thinks Danno I'll try it, if I need help I'll get with you. Thinks again John

 

you are so right!!!