If your a/c is not in working order , will that affect your secondary fan? If it works off of the a/c pressure and your freon is low or empty then wouldn't that cause the signal not to be sent. My secondary fan works when every I check for codes , but it does not work while the car is running at the specified temp .

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87 Iroc-z Black out/Grey in. 350 tuned port. Auto. T-tops.
#3 Earnhardt is #1!!

 

they will both come on when the temp reaches a certain temp, not sure of it though. cause i never used my A\C during the summer, never got over 220.

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- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series

http://www.geocities.com/david_angel_16

 

If your A/C is not working the secondary fan will not run. The stock set up only runs one fan for the engine. If you want the fan to kick in sooner pick up a Hypertech fan switch.

 

I need to clarify a couple of issues to the replies above. I am assuming the original question refers to a 1987 350 TPI. For this year, the secondary fan was controlled strictly by the fan switch located in the passenger side head. It has absolutely no interaction with the A/C. The temp switch is set at an incredibly high 243 degrees!!

So when the fan turns on when in diagnostic mode, it is not the secondary fan that turns on, it is the primary fan (driver's side) only.

Read my fan article in the tech section on this website for more information on fan function.

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Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
Former Paxton (6-psig) with 50-hp nitrous: 12.043 @ 112.86 mph.
ATI D1SC (10-psig): 12.056 @ 116.62 mph.
All stats are altitude corrected for 3,100 feet using NHRA's Altitude Correction Table.

http://willie.camaro-firebird.org/

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.