I have the green/white stripe wire that connects the fan switch to the fan relay grounded with a toggle switch so I can run the fan when I want to. I had the toggle switch off, and the fan wouldn't come on till I turned it on. Manual override works, but it didn't seem to wanna come on by its self. Would this be a bad relay, or a bad fan switch? This is my 92 5.0 TBI.

 

how did you wire it? did you splice into the wire on the relay, or did you cut it off entirely to run to a switch? if you cut it off, then the automatic control has been disabled (possibly). also, the stock fan doesnt usually turn on until north of 220*

 

I spliced in to the wire by the firewall. Anywhere between the switch on the block, and the relay is will work, although I recommend the firewall area. If I unground the green/white stripe wire, it simply comes on and off as it's designed, although I think 225 is too hot.

I found out my switch on the block is probably bad. If the relay is bad it wouldn't come on even if I ground the wire.