Radiator fan switch

[macalfie]

Hi all how would I test this I have tested the plug by crossing the pins and the fan works on both speeds would putting the switch in boiling water when not in the rad should this make the fan come on cheers

[itchyfeet]

you could test it like that but I'd be worried that the boiling water may damage the connector or wires so be careful.

should be 87 degrees for stage 1 according to Brickwerks

http://www.brickwerks.co.uk/index.php/r ... ch-t3.html" onclick="window.open(this.href);return false;

[CovKid]

If you have any doubts as to whether it works correctly or not, just buy another. They don't tend to last that long and according to Martin were a common replacement at VW outlets even when T25s were barely two years old. Its too easy to forget the temp needle and cook your engine. Just swap it out. The alternative is to leave the switch where it is and fit a modern digital probe/switch that is more accurate but it'll need setting up and probably more hassle than its worth. I've gone through two rad switches in 6 years so draw your own conclusions.

A boiling water test won't be accurate enough to draw any meaningful conclusions. Chances are its no longer reliable and a new one is needed. Temp should stabilise at just over halfway on needle, if its higher than that before fan kicks in, switch could indeed be faulty.

[macalfie]

Cheers guys I did change it last year and haven't done 1000 miles since may have been a faulty one just wanted to prove and see the fan come on just ordered a new one .

[colinthefox]

I test mine every year. After a drive of at least 20 mins on a warm day, I leave it idling. After about five or ten minutes the fan kicks in (or not if the switch is knackered), then cycles on and off every few minutes. Admittedly this only tests the first stage of the switch, but that will cope with most circumstances, and gives me confidence if we get in a traffic jam any time.

I did once cover the rad with cardboard to test the second stage, but can't be bothered with that any more.

I also carry a spare switch. The existing (GSF supplied) one has lasted ten years.