I installed the Hypertech secondary fan switch two days a go. It went pretty easy. I thought I would pass on a couple of tips for any one else doing this.

First, I was able to undo the switch from above. However, the wire going to the switch was not long enough to cut the old connector off and crimp on a new one from above so I had to jack up the car, support it on stands and do that from below. I had a couple of other minor things to do under the car so this gave me the chance to do them. The instructions that came with the switch indicated removing the switch from under the car. As this wire runs close to the headers I got some heat resistant covers to go over this wire going to the switch.

Second, the old switch is removed by a bigger wrench size than the new one, which is 1/16” smaller.

Third, the new switch is longer and I was concerned that I would not be able to screw it into the block far enough; however, this was not a problem. Also, I did not have to use any thread sealant or gasket material. Coolant does not seep out of the new switch where it is threaded into the block. Like always I applied a very thin coat of oil to the threads of the new switch so that if it ever has to be removed it will come out easy.

Both fans are coming on more now. The new PROM chip I recently acquired turns the primary fan on sooner to complement the 160* thermostat I have. I suspect this will be the case until next fall and winter.

 

Could have went to any auto parts store and got a secondary fan switch for any 86-87 or 89 turbo buick application and saved about $20

 

I did something similar for about the same price, and I find it vitally important
to the everyday operation of my car in the summer months.

The car does not like heat, arizona heat to be exact.

 

I just installed a hypertech on my car, but I did not update the PROM. I think its working right but im not sure,... The fan on the driver side is the only one that comes on. I am guessing that is because the other fan(on the passenger side) is still controlled by the PROM. I was wondering if you could confirm this for me.

The fan on the driver side is on the hypertech, and the fan on the passenger side is on the PROM,... Right?

 

It is the other way around. The fan on the driver’s side is controlled by the PROM the fan on the passenger’s side is controlled by the fan switch and the use of the air conditioning.

 

Humm,... If thats the case, then I fail. Looks like i'll be under the car again this weekend. I bet its a problem with the wire/connector. what else could it be,... unplug wire, take out old switch, put in new switch, plug in wire and go.

Thanks for the help with the fans. At least now i know where to go from here.

 

Be careful if you do this. Many of the parts stores will stock the same part number for both applications...I've tried.

 

the auto parts stores sell a adjustable thermostat 4 $30 then u can delete the factory relays wire the fans together then u would be able to control the temp with a turn of a **** and still come on with the ac some body c orrect me if im wrong but this is what i did and have no problems for about 3 years now