Speedo Issue

[paul_r]

Hi all

Seem to be having issues with speedo currently.

 

Everything works fine until radiator fan kicks in then the needle drops back to position when turned off. When I turn off ignition the speedo then seem to spring into life briefly then drop back to 0. Another thing that happens is that the bright 6 warning lights come on and then fade out? Could this be that the fan is acting like a generator when running down?

Any ideas, as I am scratching my head. The rad fan goes through a relay.

[IanS]

All electric motors can act as generators.

The problem of the speedo dropping to zero is probably the fan motor start up current dropping the supply voltage to the speedo, if the speedo then recovers you could grin and bear it.

If it is a problem then the fan relay will need some rewireing. I would suggest that the relay coil comes from a switched supply (this will switch the fan off with the ignition) and the power for the fan comes direct through a fuse from the battery with the fan negative going direct back to the battery this should isolate all glitches from the speedo supply.

[paul_r]

Thanks that's great. Luckily this didn't influence the IVA test when it reared its head for the first time.

Yet again great advice which reminds me why I'm a member of Rhocar

 

Paul

[paul_r]

Following on from above

 

I have now retired fan and now no interfere on speedo, good news. Bad news nothing is happening with speedo now when moving. Might leave his until after IVA retest as they said that they would only test the emissions ( what i failed on). I think that it might take some time to sort.