RA041024-2

Hi,
Just had my engine ECU replaced (with a second-hand one) due to loss of power to the fuel pump. Having just picked up the car, I noticed that the rear window defroster is now not working.
Does the ECU have any control over the function of the rear defroster? If so, is it possible for the "new" ECU to have fixed the fuel pump power problem but is now causing the defogger issue?
Any advice or information would be most welcome.
Thanks.

David.Norton

Suspect not, the power for the defogger comes from the load reduction relay (and lots of stuff wouldn't be working if that were bad), to a fuse, then to the dash switch, then to the antenna amplifier, and finally to the defogger. I would check the fuse, and if it is good then if the light in the switch comes on when you turn the defogger on the problem is after it, otherwise the switch.

RA041024-2

Thanks David for your quick reply. Light in the switch is not coming on...so does that suggest that it's the fuse or the switch itself?

David.Norton

Check the fuse first, my manual says #26, but check your owners manual, things move around. Then if it is good check your switch. Use an ohm meter to check it if it looks good, sometimes they will just crack internally, but not look blown. Or substitute a different fuse and see if it works. Keep in mind that fuses usually blow for a reason, so if it is blown you might have a bigger problem, so if it blows again you need to dig deeper. Don't substitute a bigger fuse, that is just a way to burn wiring.

RA041024-2

Thanks again David. I'll let you know what I find. Cheers.

RA041024-2

@David N - All fixed thanks. Much obliged for your interest and advice. Turned out that nothing was wrong apart from the fuse having being put back in the wrong position - #27 instead of #26 as you said.