SS Model Heat Exhanger Fan Wiring

[SliderR1]

It's a little more complicated than that since the fans original wiring runs through that serial/parallel relay setup. I also want the HE fan to run pretty much any time the car is running, which could in theory be arranged through HPtuners using the original fan circuit, I think. I haven't checked the lower limit coolant temperature on the HPtuners setting for the fans on the PCM. Based on my previous post with operational theory above, both fans run in series on 'low' then in parallel on 'high' as the PCM interprets the coolant temperature. I guess my original thinking was to tie the HE fan into the HE system some way instead of 'coding' it to do what I needed through HPtuners and the coolant temperature. Definitely a good option to consider, though.

If I wanted to use the SER/PAR relay, as described above, I'd need to route the ground wire from the Goblin radiator fan back up to the fuse box, which isn't really a big deal. I'm going to check the software in HPtuners tonight to see how much flexibility it offers on running these fans. If I did it this way, I would also gain both low and high speed operation of the fans, which probably is a good thing...

 

[ctuinstra]

ctuinstra - thanks! After posting that, I did realize what you both pointed out. It needs a ground, not a +12v. I agree what you have proposed should work. I also think it will be easier to wire up. I should be able to route a spliced jumper from the 2014 circuit (PK wire) C5-C2 pin in the fuse block to the C5 - A1 pin. Both of these have actual pins in the block - so I won't have to get into the circuit board on the top of the fuse block under the relays/fuses - which is where all the connections to the actual relay for Cooling Fan 2 are located.

I do have one question on your suggestion. I don't understand why we would need to jump, or even keep, the SER/PAR relay. The way we are wiring up cooling fan 1, the ground is going to the chassis up on the front of the Goblin, which eliminates the ground circuit (504) that was originally going. Also, if the relay is still in place, it will be nearly impossible to break the connection from the SER/PAR relay to the 532 circuit as it is etched on the circuit board. Wouldn't just removing the relay fix this problem?

Here is a picture of the fuse box connectors with labels:
View attachment 2185

You are correct that you can provide a local ground for FAN1 and discard all of the ground wiring at the relay.

I did mean to suggest to completely remove the SER/PAR relay. I forgot to include my diagram in my previous post.

I just wonder how many of these connections could be made on top of the fuse box with spade connectors and jumper wires.

I'm mobile at the moment and can't study it.

 

[Johvans]

I'm going to check the software in HPtuners tonight to see how much flexibility it offers on running these fans. If I did it this way, I would also gain both low and high speed operation of the fans, which probably is a good thing...

Let us know what you find!

 

[ctuinstra]

Let us know what you find!

Keep in mind, the factory way of running the two fans at low speed is to run them in a series circuit so therefore the voltage is devided equally between them (6VDC) each. The fans have to be of the same load otherwise there could be an imbalance between them. This is a very smart and efficient way of running the fans at a low speed to reduce noise.

HP Tuners, and correct me if I'm wrong, is only going to be able to control the on/off state of the original relays and not able to vary the voltage to each fan. So you can only use the original dual fan set up for a HI/LO operation. This may not work well if the fans are not the same load. Also it may not work well if you want one fan on LO and the other on HI for instance.

The only way to run one on LO would to be able to put another load of the same resistance value in series (or possibly a PWM fan, but that's a whole other subject). And this other load would have to be able to handle the same power as the fan, which is a hell of a lot. Your not going to be able to find a resistor to do this easily (this is why the second fan set up is so good, it acts as the resistor).

Hope all this makes sence.

 

[SliderR1]

Good points ctuinstra - I hadn't considered that. Between that and what I was able to see on HPtuners last night, I think I'm sticking to my first plan of integrating this fan to the HE pump. It appears the cooling fans lowest turn on point setting in HPtuners is around 192F. Here are some screen grabs from HPtuners..