Topic: elec fan problems

[robertsiii]

ok im stumped   fan  wont come on and run  after temp exceeds 180 .I tested toggle switch ,replaced temp sensor ,relay and checked solenoid still no go . I can manually get fan to run so its fine .   any ideas ?

[Jeffy]

What are you running, a homemade or some kit?  What parts are you using?  You mentioned a relay and a solenoid...  Where's your temp sensor in relation to the relay?  On the switch side of fan side?  Pictures?

Taking a guess, I'd say if your switch can turn on the fan through the relay then it's the temp sensor that's bad but I have no idea how you wired it.

[robertsiii]

homemade   towncar fan  cole hersey solenoid. bosch relay , basic toggle , cant run fan when wired correctly

[robertsiii]

brand new temp sensor installed today. should call at 180 shut off at 165 .

[Jeffy]

So did it ever work or are you doing this for the first time?  Seems a bit convoluted.  Why not just run one relay?

Do you get power from the relay leg that goes to the solenoid?  Have a multi-meter to check?  That will tell you if your switch circuit is working.  You should also be able to trigger the solenoid to turn on by itself as well.  If both circuits work then it should work.

[robertsiii]

been working for 3 yrs . ive changed parts out over the years , relay  temp sensor . it always worked fine . ill do some more trouble shooting in the am

[sharpxmen]

what does the solenoid supposed to do in that circuit? (is it to cut off the spike?)

[robertsiii]

temp sensor engages relay which engages solenoid to run fan . kept burning up relays so I put solenoid in line .

[Lah2420]

At the temp it is supposed to work, test to make sure the temp sensor is actually putting out a ground. According to your schematic, it should apparently ground itself? If so, where is it getting its ground?

[sharpxmen]

temp sensor engages relay which engages solenoid to run fan . kept burning up relays so I put solenoid in line .

it doesn't really make sense, just use a bigger relay, you don't need a 200Amp solenoid to run an electric fan - I do hope you have a separate 12v wire going to the solenoid from the battery, otherwise it won't save the relay at all (if it is just like the diagram you posted would be worse than without the solenoid).

anyway, if it runs when you jump the temp probe then it's fine, otherwise check to see what's missing.

You should also be able to trigger the solenoid to turn on by itself as well.  If both circuits work then it should work.

I think he just has them in series which makes absolutely no sense and adds another load to the circuit (but we'll wait to see if he's got another +12v going straight to the solenoid in which case would be somewhat ok)

[robertsiii]

it doesn't really make sense, just use a bigger relay, you don't need a 200Amp solenoid to run an electric fan - I do hope you have a separate 12v wire going to the solenoid from the battery, otherwise it won't save the relay at all (if it is just like the diagram you posted would be worse than without the solenoid).

anyway, if it runs when you jump the temp probe then it's fine, otherwise check to see what's missing.

I think he just has them in series which makes absolutely no sense and adds another load to the circuit (but we'll wait to see if he's got another +12v going straight to the solenoid in which case would be somewhat ok)

             

yes the solenoid has power straight from battery .   replaced the spade connector on the temp sensor wire , it was makin and brackin - that was the problem

[robertsiii]

                           

At the temp it is supposed to work, test to make sure the temp sensor is actually putting out a ground. According to your schematic, it should apparently ground itself? If so, where is it getting its ground?
[/q

yes the temp sensor is the ground in the circuit , it is installed in the intake manifold

[sharpxmen]

             

yes the solenoid has power straight from battery .   replaced the spade connector on the temp sensor wire , it was makin and brackin - that was the problem

in all honesty i would just ditch the solenoid and go with a 50 or 60 amp relay (just make sure wiring is sized accordingly) - that solenoid is overkill but yeah, will take a lot more abuse.

yes the temp sensor is the ground in the circuit , it is installed in the intake manifold

intake manifold? what's that got to do with water temp? is it a TBI with heating plate? (can't remember if that's the way they are but possibly)

[robertsiii]

heres picture of were I put sensor  it is tbi 

[sharpxmen]

your sensor should be past the thermostat otherwise you're starting the fan when you don't need to (as in the thermostat is still closed but you get your engine at 180F and the fan starts, you're cooling the water in the rad that is not hot yet. Something to consider.