MALIBU Temp sensor or wiring

[Ratchet]

The dual electric fans on my 81 Malibu will not come on when the car gets hot (OE dash gauge shows 240*). The engine is a 350 SBC with an aluminum intake. The fans will only come on when the relay is jumped. The temp sensors are new. There are two sensors on the intake. One is for the gauges and the other (I thought) is for the electric fans. The sensor for the dash gauge is wired to the green wire coming from the dash. Any and all suggestions will be a great help.

 

[spidereyes455]

Some pics and more info on the setup would help with a diagnosis. The only G bodys that came with an electric fan were the 86 and 87 turbo Buicks. So I would have to assume it's something you added in which case there would not be any wiring in the factory harness. If your still using the factory ecm one would be for the guage and the the other for the ecm temp input but not for electric fan activation. A factory electric fan switch would be usually mounted in the passenger side cylinder head and look like this.

 

[pontiacgp]

sounds like you have the relays wired incorrectly.

 

[Ratchet]

To help answer some questions spidereyes has about the installation the car is an 81 Malibu with an aftermarket aluminum radiator with dual electric fans. The motor is a 96 350 Vortec with an aluminum intake with a 600 double pumper.
The blue wire leading into the relay is the power wire from the fans. The black wire exiting the relay is wired to a temp sensor on the intake manifold.
The red wire exiting the fuse (fuse is good) and white wire are in question. At this point I am not sure what they connect to.

 

[pontiacgp]

on the relay #30 is the constant power, #86 is your switched power, #87 goes to the thermal switch and #86 goes to the + fan wire. If you want to install a bypass toggle switch tap into the wire to #87 and install the toggle switch to ground

 

[Ratchet]

When I pulled the relay apart here is what it looks like:
86 = white wire
30 = red wire
85 = black wire
87 = blue wire
Let me know if this is correct.

 

[pontiacgp]

When I pulled the relay apart here is what it looks like:
86 = white wire
30 = red wire
85 = black wire
87 = blue wire
Let me know if this is correct.

what matters is what the wires are connected to

 

[565bbchevy]

 

[Ratchet]

Thank you. I will provide an update on my progress.

 

[Ratchet]

I wired it up exactly as the diagram shows using a two pole toggle switch with the black wire (#85) going to one pole on the switch and a grounded wire going to the other pole on the switch. With the car running and the switch in the ‘on’ position the fans did not turn on.