2G Fans only come on with AC button

[Jonnychance]

It looks like my fuses for the high fan with my radiator fans are gone if I'm reading the picture below right. If I am, would those two fuses make my fans not come on and my car overheat after driving, when I'm at idle?

 

[ThunderChild]

I'm assuming you have a 2g? Helps if we know what car you're working on.

Those empty slots are relay positions and I don't believe you use those ones, I don't recall for 2gs. The relays below the empties are also fan position related, I believe high and low speed for each fan.
I would check your coolant temp switches and for voltage at the relays/fuses, as well as verify if your fans actually work, which you can do by jumping them to 12v.

I dont have the diagram handy, but maybe @dustyboner or @luv2rallye can help out there.

 

[Jonnychance]

Lol yeah sorry I got a 2g dsm. Where are the coolant temp switches located?

 

[ThunderChild]

Should be one in the thermostat housing for the a/c , and maybe one in the radiator. I know the 1gs have two like that, can't recall for the 2gs. There may also be a single wire gauge sending unit and a two wire ECU sending unit.

I just did them in my 90 laser, replaced them all, it's about $80-90 worth of sensors, but worth it. Test them first though.

 

[Jonnychance]

The shop just changed my thermostat, since a hose blew and I cldnt get to it. Maybe they messed up the sensor sense it's in the housing?

 

[motomattx]

The 2g doesn't use a fan switch like the 1g does, its ecu controlled based on a coolant temp sensor, there are two coolant temp sensor's one for the gauge and one for the ecu, if the fans come on with the a/c then that proves that they work electrically and that the problem is that they are not being commanded on by the ecu.

 

[ThunderChild]

Thanks for the clarification Matt!

 

[Jonnychance]

Okay so I have to change the coolant temp sensor for the ECU? That's what I was thinking

 

[ThunderChild]

Yes I would start there.