1968 Bronco Temp Guage

[frhrwa]

hope that's how you spell guage... anyway... have replaced the temp sending units on the engine twice, have run new wire from sending unit to back of temp guage, have replaced guage cluster... no avail... it still does nothing? and yes I have coolant in the engine... any clues would be appreciated.. maybe what I should read on each leg of the temp guage in the cluster? or, maybe I got two bad temp sending units? I hate these kinds of problems.. its probably so simple too...

[HomeBrew]

Wayne, i had the same thing happen on my 73 MachI. The gauge tested ok as did the sending unit. My problem was the regulator which feeds pulses of current to the gauge. If it stops working,your gauge will appear dead. The sending unit just supplies a ground for the gauge,so if you have a new gauge and unit, your problem sounds like the regulator.

[Bernius1]

A few more things to consider with Ford gauges:
A) many older vehicles had a 5V regulator on the
edge of the PC board which looks like a
cicuit breaker. when it fails, all the gauges
go wacky.
B) SOME use a shielded wedge-base bulb (like a
#194,but not) as a resistor/regulator. This
is more common on GM cars.
C) Ford fuel gauges can be either LINEAR,
LOGARHYTHMIC (yes,it's musical !!!) , or
INVERSE-LOGARITHMIC. The senders and gauges
must match, or the gauge will dwell too long
near full or empty.<p>One consideration for research would be either
VDO's website , or www.beede.com. They have
multi-gauge assemblies.
Good Luck !!!

[Crowbar]

You can use a 10 ohm and a 73 ohm resistor to check the operation and calibration of the guage.
Simply connect either one to the sender wire and ground. The 73 ohm will read low and the 10 ohm will read high. If you don'r get a reading the problem could be the IVR or the guage. Does the fuel gauge work correctly? If so then the IVR (instrument voltage regulator) id not at fault and you likely have a bad guage. You can also check the sender wire with a voltmeter looking for a pulsed 7 volts, this will also check the IVR.

[dacflyer]

hey, i had same problem with a bad regulator on a chrysler 77' van... made the guages go whacko.. if i had a full tank of gas. the guage said empty.then it went full as it go empty..most of the guages read backwards it seemed...anyway, thought i'd share...