Wiring a Volvo fan?

[crawlin68]

So I went down to my local pick n pull yard and picked up a Volvo fan with the relays. Now I have a question for those of you that are running this fan. How did you wire it? I am assuming the big black wire is the ground and the big red wire is hooked up to 12 volts, but where did you hook up the small brown and yellow striped wire and the orange and green striped wire? I would think that one of these would need to go to my water temp sensor to tell the relay when to kick on and off, but which one? And then where does the other one go?

[ProudPapa]

Re: Wiring a Volvo fan?

One of them goes to your muffler bearing and the other goes to the flux capacitor. For the life of me I can't remember which one is which. If you hook it up correctly you'll be able to make whiskey from your tail pipe at 88mph. But if you hook it up backwards God help us all and I'm heading for the hills! Hope that helps!

[plug ugly]

Re: Wiring a Volvo fan?

correct. one is low speed, the other high. I forget which is which. I recently tried to use a new temp sender switch and it wasnt working for some reason. But works when I put it to a normal switch for ground. Havent looked into it any further

[Efibroncoman]

Re: Wiring a Volvo fan?

I didn't use the Volvo relays. I used a 2 speed controller from DC Control.

[crawlin68]

Re: Wiring a Volvo fan?

One of them goes to your muffler bearing and the other goes to the flux capacitor. For the life of me I can't remember which one is which. If you hook it up correctly you'll be able to make whiskey from your tail pipe at 88mph. But if you hook it up backwards God help us all and I'm heading for the hills! Hope that helps!

But I have to do this before the Libians show up!!! LOL!

[ProudPapa]

Re: Wiring a Volvo fan?

I knew I could count on you to add to the story!

[California Monkey]

Re: Wiring a Volvo fan?

Doc!

[crawlin68]

Re: Wiring a Volvo fan?

I hooked everything up temporarily just to test the fan and it works great. Hi and low speed work just as they should. Now what I don't know is if I can somehow wire the hi and low ground wires from the fan to my water temp sending unit on my EFI engine and still have the two speed operation of the fan.

[earlybronco72]

Re: Wiring a Volvo fan?

Mark Harris said something about volvo relaeys and a BMW controller. Another friend also mentioned it on Facebook. Maybe you can google it.

[welndmn]

Re: Wiring a Volvo fan?

I used mine with the BMW switch, I just welded in a fitting on the radiator the tapped it out to the metric bmw switch.
Loads of info here
http://www.nastyz28.com/forum/showthread.php?t=200028

For wiring, I saw people used a relay to control the relay pack, I just did it normally, red to pos, black to neg, the 2 center wires on the Volvo relay go to the BMW switch (3 prong), then a wire from the BMW switch to a dash switch to control ground.
I did put diodes on the fan motors high and low speed wires to help get rid of the ground field those fans produce.

[plug ugly]

Re: Wiring a Volvo fan?

I did put diodes on the fan motors high and low speed wires to help get rid of the ground field those fans produce.

can you explain this further please. what is the ground field.

[welndmn]

Re: Wiring a Volvo fan?

Since the fan motor is an inductor when the contacts of the relay open, the energy that is stored in the motor has no place to go. The voltage increases (negatively) and a spark is created across the relay contacts.
I used a 1N5404 which is rated at 3A, 400PIV.

[plug ugly]

Re: Wiring a Volvo fan?

what does the spark cause, quicker failure?

[welndmn]

Re: Wiring a Volvo fan?

Yup, it can melt the windings in the fan. I noticed as when I turned off my fan from the dash (breaking the ground) the fan would run and just slow down (lessing the field) until it did not spinning fast enough to generate a negative field, it would then stop.

[crawlin68]

Re: Wiring a Volvo fan?

Was this not a problem in the Volvo cars from the factory? Just wondering where this problem comes from?