Wiring Of Guages Help

The Simps · 24-07-2004, 16:05

Hello all.

Been fitting 3 new Revotec guages to the nova this afternoon:- Oil Pressure, Water Temp., & Voltmeter.

The Voltmeter works fine as does the Oil Pressure guage. The Water Temp (WT) doesn't want to work at the same time as the digidash. ie if I connect the sender wire straight to digidash - digidash works, sender straight to guage - guage works, connect all 3 up and only the digidash works???

Any clues?

The guages are connected up to ignition live in series. They all have independant earths going to chassis. The Oil & Water guages take their sender wire from the back of the digidash. So why does the Oil share but not the water?

Any help appreciated.

Simps.

shakey1975uk · 24-07-2004, 16:19

if u want the water gage to work u will have to connect it in parrellel with the other gage otherwise in series the one that takes less current will work hope this helps paul

The Simps · 24-07-2004, 18:22

connect it in parrallel, does that mean I have to take another wire off the sender?

Simps.

shakey1975uk · 24-07-2004, 18:39

if there r 2 wires coming out of the sender then take 1 from the live side to ur other gage and the other wire to the otherone on the gage this will then be in parrellel meaning both gages should receive the same currant and same voltage obviousley there may be a bit of diff as no two gages will ever read the same hope this helps if still not sure pm me and ill send u a pic of what i mean

Andy K · 24-07-2004, 18:40

I don't think you will get it working. Better off using the 3 gauge for oil temp.

shakey1975uk · 24-07-2004, 18:41

u will get it working as i am an auto electrician so this is my job to know thanks paul

Andy K · 24-07-2004, 19:02

It might well be possible.

shakey1975uk · 24-07-2004, 19:05

so andy how can it not work

Andy K · 24-07-2004, 19:23

Well, there are a few things to think about.

1) Connecting it in parrallel will reduce the resistance across the gauges, which will mean it is inaccurate. I'd rather have 1 accurate one than two inaccurate gauges.

2) Connecting in series, will also not help because your increasing the resistance. And again inaccurate.

3) The only thing I could think off, would be to open up the digital dash and cut out the load resistor, however, this would only be a good idea if the aux gauge is specifically design to run off the vauxhall sendor. Which I doubt it is.

So basically, if you want an accurate gauge. Don't connect the new one up. use it for oil temp. It will look prity and do something usful

shakey1975uk · 24-07-2004, 19:28

i take ur point andy but the only thing he will have to do is try it its easyer to do when its in my drive with all my tools and to have the car there at hand but like i say all he can do is give it a try

Andy K · 24-07-2004, 19:31

he already had it connected in parallel, in the first place.

shakey1975uk · 24-07-2004, 19:52

he put he wired it in series u will find

The Simps · 24-07-2004, 20:04

I had the wire from the sender into a block along with te wire going to the new guage. The otherside of the block went to the dash.

I've just left it to the new guage and been for a ride. Its reads around 40-50 all the time. I've got a Courtney cool running stat fitted but should it be that low? I thought most cars run around 90-100??

So if I wanted to connect it up to oil temp what colour wire is it?

Simps.

Andy K · 24-07-2004, 20:10

doesn't sound like it's reading right, does it.

You need to fit another sensor if you want oil temp. Odders can advise, fitting a sensor into the grubscrew, on the side of the redtop head.