Fan Switch - how to test if its faulty??

1st January 2011, 18:08

chaps, i've just finished my car 1.4 Saxo Exclusive - had head gasket failure. it's all back together now.

I started it up to bleed the system, the temperature gauge rose nicely, quater way....half way....3 quaters then almost to red (warning light came on) .....BUT the radiator fan never kicked in..........i tried it a few times but it never started.

anyways - i have tested the fan but putting Live and earth straight to the battery, the fan worked fine! i have also test the wires for continuity, they were all fine.....

the only thing i wasnt sure about was the fan switch near the top of the radiator - I put the multimeter on the 2 pins but they never bleeped (indicating a fault)........so i took the switch out an put it in a bowl of freshly boiled water and tested the pins again, no beeps on the multimeter.....is this buggered? or am i testing it wrong?

Cheers

1st January 2011, 18:26

Basically yes mate as you`ve eliminated all other possibilities nice to see someone using logic & going through testing

Steve

1st January 2011, 21:44

sweet, i just wasnt sure if i was testing it correctly.

new Fan switch it is!

i bought the car knowing the HG had gone and i know its not that big of a job to sort out. anyways since putting it back together i have come to 2 conclusions why the HG went in the first place - 1) the thermostat was knackerd (stuck closed) so i replaced that thinking it was gonna cure it....it didnt, so i had to find other possibilities, this led me to the fan switch after seeing the temp gage go so high and the fan never kick in. i am guessing this is now what caused the HG failure in the first place?

on a side note.....how would i know if the water pump was working properly? is there a pipe i can take off to check the flow or something?

1st January 2011, 22:25

From my limited knowledge of water pumps I had 1 go faulty on me several years ago the things to look for are bearing noises & leaks,but when your renewing a cambelt its good practice to renew the water pump as well.Another idea is to flush the cooling system through even take the rad off & reverse flush it will along with regular antifreeze changes help keep the fluid running smoothly without blockages and will help stop corrosion in the system.

Steve.

2nd January 2011, 16:36

FIXED!!!

fitted a new Fan switch to the radiator today....let the car get warm and BINGO fan ckick it as it should. temp came down nicely!.....i love it when a plan comes together.

now to stick it up for sale...........