I have a 69 dart convert and I have a question about the temp gauge. For some reason the car has a wire coming from water temp sending unit to a small red light under the dash that I assume illuminates when water temp get to hot but theres no way to see it unless u put your head under dash. I just removed the instrument cluster to see if maybe the reason was because the temp gauge was bad. I ran a ohm meter over all the contacts on circuit board and also did the 2 c battery test and the gauge moves about half way when doing the test. Also there are no wires on the studs coming out of the instrument cluster is that normal? My question is how in the heck can I fix the gauge to work like normal? I can get pics if it helps thanks for your time.

 

Sounds like someone deleted the gauge and installed a light?
Shoot some pictures and will try to help you get it fixed....
Welcome to the site

 

Sounds to me as if someone has "rigged" something

By "no wires" coming from the studs I assume you mean the gauge is mounted as normal to the PC board in the dash cluster with nuts. The gauge normally has no wires and neither does the fuel gauge. Only the ammeter has wire connections. The temp and fuel gauge is connected through PC board traces

The "usual suspects" in cluster troubles are as follows:

PC board pins loose or broken: The pins don't make contact with the board traces or become broken. You must solder / repair them, or buy "repop" boards

The IVR (gauge regulator) goes bad, you must replace it. There is a couple of different solid state replacements, RTE is one.

The IVR socket contacts are springy contacts and can lose contact with the board traces. You must solder jumpers across to the board traces

The guage use "fake" nuts and can lose contact between the gauge studs and the board traces

The gauges themselves can be bad or out of calibration

Once you get all the above "fixed" (you think) you can use resistors to check them. You use three resistors to imitate sender resistance,

L = 73.7 Ohms (empty)
M = 23.0 Ohms (1/2)
H = 10.2 Ohms (full)

For example, you can go to Radio Shack and buy a 4 pack of 100 ohm, 1/2 watt resistors and wire all 4 in parallel which makes 1 25 ohm resistor, close enough to 23 ohm.

Substitute this to ground for either the fuel or temp sender, leave the key on for a minute, and this should drive either gauge to exactly 1/2 scale if they are in calibration, and if the voltage limiter is working properly, and all your wiring is "fixed."

 

this is sending unit on intake


the blue wire coming from sending unit and you can see little red light at top left


this is how the cluster came out with only the one harness connected beside the cluster lights and stuff. The fuel gauge works

 

The OEM temp sender, is the sender with the black boot.....
The sender with the black boot is the one that goes to the gauge on the dash....
The other one was added on...

Guess you can have to much warning...

 

ok checked that sensor and it was reading 290-300 ohms and the continuity of the wire from sender to instrument cluster was ok it wasn't a open circuit. only thing is the wire from sender is brown and at instrument cluster is violet so thats kind of throwing me off..

 

Go To the MyMopar site and get a wiring diagram..Check under Tools and references. :0
That will help you under stand...

 

Looks like Violet all the way threw? But Ma mopar dose do some funny stuff....

 

You have two senders there..............the one to the left with the black boot is the original. The one with the blue wire has been added...................