bigoldscruiser

I have read in the past where some of you guys used electric fans from Dodge Intrepids to cool your Olds. I have acquired a dual fan setup from a 1999 Intrepid and need to know how to connect it. I tested the motors and they run by grounding the black wires and putting 12v to either the yellow or green wire. Why both and which one should I be using?? Thanks for any help you can offer. Bruce

bigoldscruiser

It looks like with a little playing around, I have answered my own question. If you put 12v to both the yellow and green wires at the same time, the fans run faster. It doesn't seem to make any difference which you run alone for slower speed. Can anyone verify or dispute this??

Frankenstien

Sounds to me like there should be a switch that these fans should connect to. This allows some regulation of when the fans run or how fast they run. Seeing as they are electric, they should be able to be regulated based on how hot or cool your motor is running. Just a thought. It may be totally off base.

Oldsguy

I agree with Frankenstien. If you want to duplicate that you will need two engine temperature sensors each set differently. The problem is since the fans were used in a different application you don't know how they will cool or perform in your car. Slow might be sufficient or the fast speed might be necessary. I would suggest just using the high speed and going from there. There are some other posts on using electric fans on this site and I recall that someone recommended using oil pressure as a trigger too. It was probably Joe that said it.

edit: you might go back and find the engine sensors that were used in the Intrepid if you want to duplicate that set up exactly although you will probably have to use adapters to mount them on your engine since they may not be correct size or thread pitch.

1966_F85

It is easy to set up, Hayden has a few switches you can use and they are adjustable so you can set when your fans come on. It all depends on if you want the probe in a hose or an actual thread in temp sensor.

Here is an example of one I used for my 67 Nova - it threaded right in where the idiot light sensor went: http://www.summitracing.com/parts/HDA-3651/

bammax

Sounds similar to the LT1 fans. The system is grounded and at a predetermined temp the pcm turns on the primary fan at slow speed then high speed then if needed it'll turn on the secondary fan also.

You could run a single wire temp sensor (dummy light style) that will operate as the ground and then run power through a relay with the sensor working as the switch.

If you wanted to get creative you could run dual relays per fan and run dual sensors so that the fans would switch from low to high speed when a higher temp is reached.

Or you could just run the primary through the temp sensor and the secondary through a manual switch to have more control with less fuss.

If you need any wiring guidence I can provide some rough schematics to play with for any of the options you choose.

texasred

My plan with LT-1 fans (car still in build stage) is an ignition hot to a relay for low speed and a 165 degree thermostat switch to relay for high speed. Of course, I'm in Texas and need all the help I can get.

Also, I have a high output alternator to keep it all happy. :-)

C.J.

bigoldscruiser

Thanks very much for all the input, guys. My main concern is traffic jams in very hot weather. I just experienced that on the way to the Nationals in Mass. We were stuck for 45 minutes with no way to get off the road and the air temp was very near 100 degrees. The temp gauge got up to 250 degrees and shutting the A/C off and revving the engine did not help much. It did go down once we got rolling but I don't want to do that again. I will be putting the new fan system together over the winter.

bammax

If you run an ignition hot straight to the low speed side then the fan will be on anytime the ignition is on. If you run it through a relay then you'll need a switch of some sort to trip the relay when you want the fan to come on.

The LT1 fans are designed to run at a constant speed with one fan acting as the primary and triggering at 190 and another fan running as the secondary and set to turn on at about 220. Basically the primary runs when the temp guage reads straight up and the secondary comes on when the guage hits the red zone. It's scary for those who haven't seen it before since you'd expect the secondary to come on much earlier.

Running LT1 fans as variable speed tends to decrease their lifespan a bit. Another thing to keep in mind is if you are looking to score a set from a junkyard then try to get a pair of secondary fans because they'll have less hours on them since they only come on for short bursts in extreme cases.