mikem77

I have searched and read as many of the fan wiring threads as I can find. I am fairly new to taking on the electrical sides of vehicles and want to make sure I get this correct. I have a LQ4 in my '72 Nova with a Be Cool radiator and Be Cool dual 11" fans. I have a PCM from Speartech with wiring leads for the fans. I want to use 3 relays and have found a couple different wiring diagrams. What I haven't been able to find is specific information about the Relays. Like I said I am new to the electrical side of vehicles. Are there any specific relays I should be looking for or will any single pole relay work?

Thanks in advance

oange ss

iTrader: (50)

yes, just make sure thay have enough rating for your use

Pop N Wood

iTrader: (1)

Cheapest place to get fan relays is a pick and pull. If you are buying something else they will usually give you the relays for free. You can usually grab them off any POS ford in the yard with little or no effort. If you grab them off the fan of a Taurus then you know they are rated for the current.

John Dingman

Here's a copy of Spals fan wiring diagrams. We use it for the same Spal dual 11" that you got from BeCool. We can sell you the wiring and relays if you want. Why do you want a three relay system?

http://www.dewitts.com/download/FRH.pdf

clm69z28

Here is the schematic that I used to build the three relay fan control that is found on this forum. It works real well and is very quiet. I do remember that there is a certain relay that you need to use to be able to switch from series to parallel; not all relays can handle that function as designed here. Below are the specs on the relays.

50 AMP Relays AWS-75311
Relay Sockets AWS-RBKTM

Palomba

iTrader: (1)

i got 3 regular 40 amp relays from radio shak for like 5 bucks each. Then wired them in myself.

Gray86hatch

iTrader: (83)

Use the Spal relays they are OEM weatherpack and plug right into the fans.

Never had a problem with them.

Tim

chpmnsws6

iTrader: (70)

http://www.texasindustrialelectric.com/relays.asp

for my Taurus fan setup, I ordered a 70 amp 5 prong relay for the high speed and a 30/40amp relay for the low speed, both with small resistors in them to help keep the relays healthy.

80 MONZTA

About what size resistor, and where are they placed in the circut?

Marky522

iTrader: (8)

They arent resistors, they are diodes, to stop the flyback voltage that is created when the magnetic field collapses within the relay. HTH

Mark

chpmnsws6

iTrader: (70)

They are actually resistors, and I do not know what size. The person from that company said the resistors are more forgiving then the diodes and will do the same thing.

Marky522

iTrader: (8)

600 ohms or greater, I didnt realize they used resistors till now, http://www.autoshop101.com/forms/hweb2.pdf gives a very good explination of relay function, and the voltage induced back into the circuit. A resistor isnt as efficient as a diode, but is more durable.

Mark

clm69z28

The type of relay is a resistor or diode protected relay so that the voltage spike doesn't damage your ECU. Regular relays will not have this protection built in! I incorrectly stated that it had to do with the change from series to parlallel. Getting old sucks!

Nashty

iTrader: (7)

Relay 1 must be SPDT (5 prong w/ a normally closed circuit), the others are just SPST (4 prong).

Another thing I did is to go to U-Pull-A-Part and get an integrated relay pack with a built in fuse. Mine came from a 92 toyota Corolla. It has to be re-pinned and wired but it has the correct (3) relay recepticals & a built in heavy duty fusible link (fuse) slot. It's sealed & weatherproof and once done, compact and looks factory.

Palomba

iTrader: (1)

I bought 40 amp relays from radio shak for a couple bucks a piece.