90 5.7 TPI

Just noticed today that my pass. side fan doesn't come on.
The drivers side will turn on with the A/C turned on or the engine comes to temp.
I thought the drivers side fan was the primary and pass. side fan was for the A/C and over temp.

I have the manual but wont have time till next week to trouble shoot and trying to find the probable cause.
Thinking it might be the temp sensor in the pass. head and/or the connector?

Thanks for any help

 

On a 1990 5.7 TPI which is the primary fan, drivers or passenger ?

 

Pretty sure the primary is on the driver side which is controlled by the ECM and set to come on at a certain temp etc.

When you get a chance take a look at the passenger side head near the knock sensor, I bet you will find a burned up/ broken connector or wire damage to the fan temp sender.

This post has some really good info on the TPI dual fan set up, Deadbird explains it clearly.

1989 IRCO 350 TPI Dual fan operation - Third Generation F-Body Message Boards

 

Reddragon88gta

Thanks for the info and the link.

I read both the linked page and the one referenced and still have unanswered issue.

My drivers side fan comes on with the A/C and temp switch. Which temp. switch will need to be determined.
Pass. fan does not come on at all.

It seems that my fans are wired backwards, I don't think this is the case as I'm the original owner but did have the engine modified by a performance shop back in the 90's. I will look into this.

I'll test both temp switches and check wiring next week as time permits.

 

Here is how my 1990 LB9 works, I would image your would/should work the same. https://www.thirdgen.org/forums/cool...ervations.html

 

LiquidBlue

Thanks for posting!!!

Going to replace the connector for the sensor on the pass. head as it looks very suspect.
Will do your test after

 

Pulled the connector off the pass. head and found it was modified because of contact with header.
Reinstalled modified connector and zip tied it to sensor.

Fan now working as it should.

Thanks for the help