ahdoman
Dec 27 2006, 11:12 PM
I have an oil temp gauge in my center console. It appears the PO unwired the temp gauge above the fuel gauge and wired the send to the one in the center console. Can I run the two gauges simultaneously? It's not mandatory it's just I don't like having a gauge not working. If I can how should it be wired?
markb
Dec 28 2006, 01:17 AM
You need to make sure the sender is correct for the gauge. I doubt both gauges use the same sender, but I've been known to be wrong before.
John
Dec 28 2006, 02:21 AM
I believe that if you try to run both gauges from the same sending unit that neither gauge will read correctly. (at least they didn't in my car)
I had the center console gauge and a fuel/temp gauge both installed in my street car when it was a 2.0 and at one time I wired both up. Both gauges would function, but each read about 1/2 what they should have. I didn't calibrate them, just an approximation.
I went back and removed one of the two gauges and all was normal.
Just my experience.
ejm
Dec 28 2006, 06:45 AM
Gauges work by measuring the resistance to ground through the sender. If you hook two gauges to the same sender each gauge will see a ground path through the sender and the other gauge causing incorrect readings. Using a couple of diodes between the gauge and where the sender wire splits should allow both gauges to read correctly. In theory anyway

Diodes allow current flow in one direction only and would block each gauge from seeing two ground paths. Radio Shack has packages of diodes for a buck or two if someone whats to try it out.
McMark
Dec 28 2006, 10:26 PM
Hook up the dash gauge, get a CHT gauge for the console. Problem solved.
markb
Dec 29 2006, 12:58 AM
QUOTE(McMark @ Dec 28 2006, 08:26 PM)

Hook up the dash gauge, get a CHT gauge for the console. Problem solved.

ahdoman
Dec 29 2006, 09:55 AM
QUOTE(McMark @ Dec 28 2006, 08:26 PM)

Hook up the dash gauge, get a CHT gauge for the console. Problem solved.

What is the difference of a CHT gauge vs. the VDO? Besides, I already own the VDO and everything else is also VDO (oil pressure, clock, head temp) so it needs to match.
John
Dec 29 2006, 11:42 AM
CHT Gauge = Cylinder Head Temperature Gauge
Joe Bob
Dec 29 2006, 11:45 AM
One's a brand name the other is not....VDO does make a CHT....the sender ring goes around the spark plug in most cases.
ahdoman
Jan 4 2007, 10:32 AM
Per my original post.. I have both a head temp gauge and a oil temp in my center console (along with an oil pressure and a clock). What I want to do is parallel the oil temp in the console (VDO) with the one in the factory (gas & temp) gauge.
Ed - the diodes seemed to do absolutely nothing. If I hook up both gauges they do indeed change the resistance value of the sender and both read an incorrect lower temp.
Does anybody know the resistance value of the oil temp sender? Can I wire a couple of resistors in line with the gauges to re-create the value the sender wants to see?
Demick
Jan 4 2007, 11:15 AM
Why do you really want two gauges that show the same information?
I don't think there is any reasonable way to get both to work properly from the same source - especially given that there is a 90% chance that they are calibrated for different resistance senders.
I'd just focus on getting one gauge to work properly. If it was my choice, I would get the combo gauge to work correctly, and scrap the center console gauge. If you need to fill the extra hole in the center console - just get a volt gauge.
Demick
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