Electric Fan Switch Swap
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Instructor
Joined: Nov 2001
Posts: 164
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From: Columbus oh
Electric Fan Switch Swap
I seen a lot of you have modified your cooling fan to come on at lower than 228*. Being a new owner, Im not comfortable with that temp either. I know I have to change to lower thermostat. To change the fans turn on/off points, is all I have to do it change the fan control switch by the dipstick on the right cylinder head? That was all I had to do on my other car. Ive seen kits that run several hundred dollars, and cant figure that out at all. Im going with a 160* since thats what works great in the other car. Any part #'s. Thanks in advance. :confused: :seeya
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Joined: Dec 1999
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From: And on the fifth day, subpoenas were served to Obama senior staff
Re: Electric Fan Switch Swap (black86targa)
Not quite sure on an 86, but believe this is correct:
If you have Z51 or the aux fan (in front of the radiator), then you have an aux temp switch between #1 and #3 on the left head. This can be changed to a 200* switch from many sources (even NAPA if they can tell you the turn on temp of the switch). This will turn on the aux fan earlier, however this alone will not control your temperature.
The stock thermostat is a 195*, so this must be changed if your goal is to lower temperature below this temperature.
The main fan, which provides most of the cooling is controlled by the ECM. The ECM uses the temperature sensor below the throttle body, however this cannot be modified as it is used for many engine management duties other then temperature.
Choices: You can change just the aux fan temp switch (if so equiped), but this alone will not make a big difference. You can install an aux switch (rreplacement) and also tie this connection to the main fan relay which will force both the main fan and the aux fan to come on at the temp of the aux switch (this is a good econ. solution). You can change the aux temp switch, and get chip blown to turn on the main fan earlier. All the above of course requires the proper temp thermostat.
Regardless of which way you go, check out the tech tips section on this forum and do the radiator removal / cleaning - this must be done.
My Choice: 200* aux temp switch and ECM programming to turn on the main fan at 195* or so. The benefits of allowing the ECM to continue to control the main fan are worth the chip programming to me. I.E., ECM still commands main fan on with AC active, and commands main fan off when over 35 MPH. I used a 180* thermostat: it runs around 175* in winter and 185* in summer on highway, hottest it has gone is 205* in bumper to bumper with some heat soaking, but went right back to 185 in short order.
Good Luck with your choice. Oh, BTW, the temp sensor on the passenger head above the starter is for the temp guage only - don't mess with that.
Pete
[Modified by PeteL, 6:00 PM 12/22/2001]
If you have Z51 or the aux fan (in front of the radiator), then you have an aux temp switch between #1 and #3 on the left head. This can be changed to a 200* switch from many sources (even NAPA if they can tell you the turn on temp of the switch). This will turn on the aux fan earlier, however this alone will not control your temperature.
The stock thermostat is a 195*, so this must be changed if your goal is to lower temperature below this temperature.
The main fan, which provides most of the cooling is controlled by the ECM. The ECM uses the temperature sensor below the throttle body, however this cannot be modified as it is used for many engine management duties other then temperature.
Choices: You can change just the aux fan temp switch (if so equiped), but this alone will not make a big difference. You can install an aux switch (rreplacement) and also tie this connection to the main fan relay which will force both the main fan and the aux fan to come on at the temp of the aux switch (this is a good econ. solution). You can change the aux temp switch, and get chip blown to turn on the main fan earlier. All the above of course requires the proper temp thermostat.
Regardless of which way you go, check out the tech tips section on this forum and do the radiator removal / cleaning - this must be done.
My Choice: 200* aux temp switch and ECM programming to turn on the main fan at 195* or so. The benefits of allowing the ECM to continue to control the main fan are worth the chip programming to me. I.E., ECM still commands main fan on with AC active, and commands main fan off when over 35 MPH. I used a 180* thermostat: it runs around 175* in winter and 185* in summer on highway, hottest it has gone is 205* in bumper to bumper with some heat soaking, but went right back to 185 in short order.
Good Luck with your choice. Oh, BTW, the temp sensor on the passenger head above the starter is for the temp guage only - don't mess with that.
Pete
[Modified by PeteL, 6:00 PM 12/22/2001]
