intercooler control system

If the heat exchanger fans are wired as instructed -- relay trigger to the intercooler pump hot lead -- the fans will be running wide open the entire time that the truck is running.  Installing an on-off switch in the cockpit is an option, but I hate having things to remember.

So I rigged the HE fans (Afco prefabbed shroud) to come on as needed.  I used a SPAL PWM radiator fan controller.  The SPAL controller has low (50% power) and high (100%) set points for the fans to come on, and will vary the power in between.

The senders shown here go to a Nordskog digital temp gauge.  The SPAL can read an aftermarket sender output, but I did not have good results using this method tapping into one of the Nordskog senders.  So I ordered the SPAL temp sender, and added another boss (3/8" NPT) to the outlet side end tank (not shown in the early mockup photo above).

The harness also does not show the wire for the SPAL sender.  I runs in the same branch as the gauge senders.  Note also that I had to change the mounting location of the SPAL after I decided to retain the hood latch (I was originally planning to use hood pins only).