I bought these used w/ no instructions and the ones I got off the manf. site don't cut it. I've tried sketching this out a number of times but can't figure out how to get it to work. Is there anyone thats good with wiring that can help?

Here are the requirements:

1 relay to direct power to fans when ignition is on (so it doesn't run with the truck off)

Needs to work with the themostat that came with the fan. It has three contact points on it and the dial to adjust the temp.

Three way switch wired, always on, always off, thermostat controlled.

They are dual fans but are wired to have one positive and one ground wire already.

Has anyone wired something similar to this before?

 

I have those instructions here somewhere for the flex-a-lite, I'll keep lookin around, in the mean time did you check with flex-a-lite fans, they could probally help you out.

 

Call flex-a-lite. I had a similar issue when I imported the truck from CA. The guy worked out what fan I had fitted from my vague discription and told me where all the instructions are on the web. They were very very friendly and helpful.

 

The problem is the instructions on the web aren't what I need. I was hoping to find someone that might be willing to sketch out a diagram or something.

 

oh, I see. I'll have a look. Do you know which fan you have so I can check the terminals avaliable on the control box?

Simon

 

Try this circuit for size....

I'm assuming you have a similar thermostat connections to me thus:
B: Perm +12V high current supply (i.e. straight off battery via 40A circuit breaker/ fuse)
+: Switched +12V from ignition.
G: Ground
M: Manual override fan ON.
C: A/C Clutch connection.

General circuit description:
High current 12V is fed to the B terminal via a 40A protective circuit breaker (or fuse) through a normally open relay contact (needs to be a capable of taking 40A or more across the terminals).

A dual pole, three way switch (ON-OFF-ON) in the cab controls the fan operation (Always On, Always Off, Thermostatically Controlled On).

In the Always ON position the fan 'B' relay is energised providing the motor power to the fan and the 'M' is energised manually turnign the fan on.

In the Always OFF positon neither the B nor the M is energised. Even if the thermostat decideds the fan should be on the lack of power to the B terminal will leave the fan off.

In the Thermostatically Controlled ON position the 'B' terminal is energised via the relay and the thermostat is left to control the fan operation acording to the setpoint on the dial.

The optional circuit in the dotted line below is a warning circuit that the fan is Always OFF to prevent the risk of the engine overheating if you forget about it. If the ignition is on and the three way switch is in the off position the normally closed contact on the lower relay will cause a buzzer to sound or a lamp to imluminate (your choice). When the switch is in the Always On or Thermostatically controlled position this relay is energised opening the normally closed contact.

Sorry the diagram is a bit scruffy - was designed over a bowl of cereals this morning. I can redraw it on Visio etc if you need but it will take a few more days. I can also adapt it to differing requirments if you give me more info.

Regards


Simon