I've using a micra rad with built in thermostat and a bike engine (for those that didn't know). I've also wired it up direct to a permanent live switch so I can turn it on manually.

It used to work fine, cutting in around 80 something degrees if I remember, but now it doesn't work.

Checked the fuse - fine. It has permanent live feeding it and it well earthed. I've removed it and put it in a boiling kettle, switches live no problem, and switched off when removed - checked with continuity tester. I don't have a thermometer so can't test is accurately.

So why won't the f**ker work when it's wired into the rad?

BTW my temp gauge is set half way down the long pipe to the rad, and it's detecting a temp rise up to 95 degrees in the pipe to the top of the rad before I cut the fan in manually. The last time I did this the radiator cap also started to bubble over.

is the motor shagged?

check that you have volts at the motor, and at the outfeed of the switch, once its on.

atb

steve

if you bridge the 2 wires on the thremoswitch do it work,if so probly a circulation problem,try raising the revs a bit and see if fan switches on

Jasper,

Assuming that your circuit is OK I would check the voltage drop accross the switch when it has operated due to high contact resistance in the switch.

Conrodkids suggestion should show whether the switch is the problem.

If you used a continuity tester it may indicate that its closed but still be high resistance compared with the load of your fan. Mine pull about 6 amps. Also check that the fan hasn't got some positions that it won't start in due to armature failure.

If no joy then with the switch closed measure the voltage at supply side, fan side of switch and earth side of fan relative to the battery 0v and post the results. We should be able to pinpoint the problem.

I had problems with the Micra cap bublin - cured with a new radiator cap.

Hope this helps.

Cheers,

Colin

Thanks guys

I think I may have had a airlock. I gave it some revs this morning to get the pump going (around the car park next door- yee-har!) and the fan came on at around 88 degrees. No boiling over.

Glad it wasn't anything more serious, I hate electrics.

So, last jobs are bonnet catches and number plates and we're done!

nice one Jasper, i remember when it was just a dream..........

Yeah - cheers for all the inspiration and bits Jon - you can have first spin at Donny this year if you like!

allready "spun" at donny several times if ya know wot i mean,

sure would love a ride.........

anyone else reading, and i'm sure Jasper won't mind me saying this, he should be an inspiration to any one thinking of building a locost, as proir to the build he had next to no experience with cars, welding ect........... and look what he built, it CAN be done.

Cheers Jon - it's only because of the support of people on this list that I've got to where I have in such a short time (exactly a year), it would have been next to impossible without it.

Stop it guys there can't be a dry eye in the house by now

Hey I've just noticed this was my 300th post. Not bad for the fifth person to join this group.

[Edited on 9/6/2003 by paulbeyer]