F.I. 57 Belair

I am finishing up my L98 Vortec engine swap into my 86 Caprice Landau and I need to buy the cooling fan pressure switch that goes in the liquid line and turns on the secondary fan if the head pressure exceeds 233 psi. I have had no luck finding a replacement at the dealer or the local parts stores. Does any body have a part number or know where to buy this switch?
Thanks for any help you guys can provide.

Tuned Performance

iTrader: (92)

Any of these work ?

https://www.rockauto.com/en/catalog/...ch+switch,4284

F.I. 57 Belair

Thanks but the link does not work. For some reason I cannot access their site to che ck. Will try later.

Tuned Performance

iTrader: (92)

F.I. 57 Belair

I finally found the switch I was looking for on Amazon. I searched for a condenser fan pressure switch for a 91 Z/28 and it is a four seasons 36669 switch. When I checked it out it fits from about 1985 - 1992 gm vehicles with electric cooling fans. I had tried napa and Advanve auto parts with no luck and for some reason I still cannot access the Rock auto web site. I even disabled my ad blocker but still cannot get on it. Thanks for trying to help me. I have a pair of cooling fans from a 1993 Buick Lesabre that I am using. The main fan has a high and low speed and the secondary is single speed. I will have the ECM turn on the main fan on low speed at 210-215 deg, the secondary will come on with the ac request signal and the main fan high speed if the ac head pressure exceeds 233 psi or the eng temp goes over the set point of the temp switch in the right head. At least that is my plan.

Fast355

iTrader: (2)

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If you are running the 7730 ECM it is easier to do than that. Add a wiring pin into the PCM for the 2nd fan output. It allows for control of both primary and secondary fans. I used it to control dual speed fans. Although it activates both fan outputs with the a/c.

F.I. 57 Belair

I will look into that. can you tell me
what pin I need to wire into and do I need to change any settings in the programming using EBL and Tuner PRO. I am new to tuning so I am looking for all of the help I can get.

Tuned Performance

iTrader: (92)

Tuned Performance

iTrader: (92)

Fast355

iTrader: (2)

Did not realize you were running the EBL. Maybe RBob can clarify this one. But on the factory code the 7730 ECM can run dual fan outputs. One is on pin F8 and the other directly across from it on E8. It does require some minor reprogramming to work correctly.

F.I. 57 Belair

I was looking over this dual fan wiring schematic you posted and noticed that it differs from the one in my 1993 factory shop manual. Your page shows the pressure switch as normally closed opening at 190 psi. I would think that would cause the fan to run at all times. The page in my manual shows it as normally open, closing at 233 psi to turn the fan on.

My plan is to utilize the dual fans I have by having the terminal E8 turn the primary fan on low speed at 210 deg, terminal D12 when the ac is on or the coolant temp switch in the right head will turn on the secondary fan when temp exceeds 234-238 deg, If ac head pressure exceeds 233 psi the pressure switch will utilize a third relay to activate the high speed of the primary fan. Here is the schematic I am following from the donor car a 93 Buick Lesabre that utilizes a large 16.5 in two speed primary fan and a smaller 12 in secondary.

Tuned Performance

iTrader: (92)

39 Buick lol, the fan have a switch flag in tuner pro.

F.I. 57 Belair

I did not catch that before I posted. I will edit the post. I understand the switch flag but was wondering how a switch that is normally closed would work, since it creates a ground to activate the relay. Guess it doesn't matter since I will be using a normally open switch to control the primary fan high speed through the third relay I have installed. It should work just like it does on the Buick donor car. Thanks for the help, my pressure switch should be here Monday so I can test it all out. If this does not work out in actual practice it would be an easy wiring change to set the fans up in a series/parallel like used on the LT1 4th gen cars to control high/low speeds.