My secondary fan is not working and I’ve mostly diagnosed why I’m just hoping you guys can point me towards a solution that does not involve a broken wire somewhere.

My main relay works great fan works great

secondary fan works great if I jumper the orange to the black/pink (or is it purple) wires at the relay.

If I check for 12v at terminal D on the diagram I have it. (Wire to chassis ground)

but when I look for power across D and F (grey wire) I do not have it.

these checks were done with aldl jumpered, also a/c on, and also verified secondary fan should be on using what’s up display on the laptop.

if I’m reading correctly the only fuse it could be also controls the alternator so if the fuse were blown I wouldn’t be charging.

any ideas?

 

Nevermind, I had been under the impression that the secondary fan was ECM controlled but that is ONLY mecahnically controlled so with no A/C pressure currently and not at 243 (factory spec switch in head) I won't get ground on the grey wire, correct?

The only way to get the secondary fan to come on sooner is a new switch in the head, running the a/c (with pressure in the system) or can I just jump the ECM switched ground from the primary relay to the same spot on the secondary relay and run both "ECM controlled"

 

A new fan switch would likely do it fine. Plenty of alternate temp switches to choose from. Doesn't rely on AC to function at all. You could have them both on at the same time but wouldn't work as well as the two temps it's originally set up for and will accelerate fan motor wear and cool WAY to much in cooler weather