Hi all.

Have a problem with my EF Fairmont at the moment...when I turn on some accessories like the air or driving at night with the headlights on, I notice that my Volts gauge goes down (to about 12V - havent measured at the battery yet...) but so does the oil pressure gauge. If I turn the accessory off my oil pressure comes up, as does the volts. Has anyone else had this issue? Is my alternator/regulator on the way out? I have a new battery installed.

Cheers

Scoots

Definately sounds like the alt causing it.

I'd be worried driving it at night mate, get it fixed or you'll end up stranded, not a good thing living that far out.

bah, this is normal.

The gauges are electronic, any load/voltage difference will change their values.

I put my AC on and the oil gauge drops nearly ½ of a ¼ along with the voltage.

A new alternator may assist, but i strongly doubt it.

Theres only small guage wires going into the cluster, hence no free lunch, current draw will have effect.

Mine been doing this for years, I've had numerous clusters and they all react the same way, same as my sisters, friends and collegues.

If the your majorly concerend, get a mechanical gauge on it and test the oil pressure

Problem is that it has only recently started doing it. I will pull into my driveway and the oil pressure gauge will drop into the red (because at idle the oil pressue drops a bit) and sound the warning alarm. As you can imagine the first time this happened I freaked. But when I turned the air and the lights off the oil pressure came up out of the red. This is oviously something I want to fix...

Well in that case I'd be replacing the oil sender unit with another one.

as for voltage, 12v on the gauge is around normal, obviously 13+ would be optimum.

Do you read low oil all the time? if so you've prolly got a really bad connection on the sender, Broken or faulty.

Put a multi meter on the alt and check voltage under load, that'll give you a good indication.

Thanks everyone for their suggestions.

If I am cruising down the road at 100k with no air or lights...fine, everything is OK. If I flick on the air then within 10 seconds both gauges will drop and when I slow down to idle and the oil pressure normally drops a bit then the needle drops slowly into currumba territory. Turn the air or the lights off and up it comes again even at idle. It was doing it only with hot weather (30+) but seems to be all the time now. If its a cluster problem, why doesnt it effect the fuel and temp. gauges? Strange...