Help!! electric fan wiring failed now car won’t start

[Deedz]

Well it has happened. I don’t post often on the forum since there is so much information I always like to do research on a topic before actually doing so, turns out I didn’t do enough and today while installing my efan I believe I might of fried my Ecu . Car cranks over but doesn’t want to start. I checked all fuses, and all are good(fan is out of a 98-00 ford crown Vic). 

 I tried tapping into a 12v switched source and after that the no start happend. Question, is there a ecu fuse or anything of sort I should check? Also I have Nissan Data scan and it’s not communicating with the ecu when plugged in. Help is greatly appreciated.

Edited October 19, 2019 by Deedz
Reason for no start

[Slartibartfast]

So you tapped into a random 12v switched wire in the engine bay for the fan controller? Or to run the fan directly? The fan takes a fair whack of power, so no surprise if that fried some other circuit that wasn't designed to handle that much extra load. I'd be more surprised if just a controller nuked something, but I guess that depends on what you tapped into.

Pull up the EL section of the manual, find the wire you tapped, and figure out where it goes. It's tough to say what would've popped without knowing which circuit you overloaded. If it goes to the ECU, pull the ECU and check that it's getting power (the EL section should have the ecu plug pinout and tell you which pins to check for power and ground). If it's getting power but not communicating, that's not a good sign for the ECU. If the ECU isn't getting power, figure out where it gets power from and check that next.

 

Also, how did you tap into the wire? If you cut it, make sure it's back together. If you used one of those Scotchlock suitcase connectors, make sure the conductor's not broken inside the insulation.

Edited October 19, 2019 by Slartibartfast

[Deedz]

Thanks to your reply, I figured it out. I looked at the schematic that you told me to and it was a fuse I didn’t think to check. Swapped the fuse and she started right up.

On a side note for anyone that’s doing/did a electric fan swap where are they tapping into for a 12v ignition source so I’m not making the same mistake?

[Mr_Reverse]

I didn't bother tapping into a switched power for any of my e-fan conversions. They have all always been hot. The fans don't run enough to hurt the battery when the engine is off. 

 

 If I was going to have it switched, I would pick a convenient circuit that isn't a critical one and use it to run a relay to feed the fan controller.