Help for testing faulty thermoswitch & fan relay.

[mx5lover]

Hi all

My 5 was overheating last Monday when I drove home from north Sydney.
Initially, I thought my fan is dead because it is kick in when the engine is hot, but after testing, it is working fine.
Ref to the Haybes repair manual, it may a faulty thermoswitch or fan relay maybe both.
I have not using a mutiplemeter before, and no idea how to test the continuenity on them.
I use the Ohms function(not sure is the correct way) to test them.
for the thermoswitch, nothing change on the multimeter whenever the engine is cold or hot.
(for testing hot engine thermoswitch,should I test it while engine runing or shut off,
what I did this morning was testing when the enine was hot but turned off)
for the fan relay, I only test it with no voltage supplied, and it shows fine.
Ref to the manual, it also asked me to test the fan relay when the voltage supplied,
but I don't really know how to do it.
does any one can tell me?
Assume the ohms function test is correct, my conclusion is the faulty thermoswitch causes
the cooling fan stop kicking in when the engine reaches hot.
Sorry for my broken english.
THX

Oujun

[Russellb]

I take it you have an NA6 ???
Quick check for the relay is to TURN ON then IGNTION( engine off but all dash lights on ) and then remove the plug from the water outlet
at the front of the motor and using a paper clip connect it to the cam cover. If the fan comes on then there is a NO problem with the relay or
power to the relay, replace switch in water outlet.
if the fan dosn't work then check the fuse in the black box neer the brake master clyinder.
If fuse LOOKS OK then remove and do OHMS check Should read 0.
If fuse test good then the relay is MORE than likely DEAD replace relay

Hope this helps

Mined you no good for any other model

[mx5lover]

thanks for your advise.
Mine is NA6
I guess is the thermoswitch problem,
I jumped TFA” terminal to the “GND” terminal with turn on igntion
the fan is working fine, and I guess the relay and the fuse should be ok.
I may try to replace the thermoswitch see how does it go.

[mx5lover]

I just double checked again,
when I connected the plug to the cam cover,
the fan works, I am going to replace the thermoswitch
and get my fans back.
Thanks again Russellb