gauges need some assistance

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kielbasavw

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My gas gauge isn't the most accurate thing in the world. Sometimes it won't move very much then next morning its a 1/4 lower then when I parked it. Other then replacing float and sender, I remember reading there are one or two other things to look at aswell.
Temp gauge reads funny sometimes, sometimes it won't work at all or get stuck at cold position while running.
Speedo needle hops arouns constantly, I read I need to grease the cable, do I just litterally pull the cable out, grease the end and stick it back in the gauge? Or is there sonething else to it?
Alt gauge is constantly in the center weather its on or not.
Random gauge lights will shut off, sometimes will come back with a hit on the dash, sometimes not. Will be off for weeks and randomly come back on one day.
 
Year make and model please? Likely culprit since both guages share a common part is your voltage limiter. It drops the voltage going to the temp and fuel gauge from 12v to 5v. On many models it is built into gauge. One of the members here sell solid state (more reliable) units I can't remember who it is.

Your other issues could be a bad dash cluster ground.
 
Do some searches on the forum. There are many threads on this

Some stuff:

http://www.forabodiesonly.com/mopar/showthread.php?t=207604&highlight=gauges

http://www.forabodiesonly.com/mopar/showthread.php?t=179517

Treat the gauges as a "system."

You start with power to the cluster, goes through the voltage limiter and splits power off to both gauges. From the sender end of the gauge, each one goes back to it's own sender.

Problems are:

PC board connectors: The pins corrode and break loose. You need to repair them and insure that full voltage gets TO the PC board.

GROUND. The cluster is not well grounded. Time, rust, makes it worse. Connect a separate ground pigtail from a ground on the PC board, run to a screw/ nut on the column support, etc

Voltage limiter: These go bad. One my 67, the "socket" itself consists of brass contacts which were NOT making contact with the board traces

GAUGES: Can become innacurate over time, and the studs lose their contact with the board. Replace the "fake" nuts with real ones, and tighten/ loosen/ tighten the nuts to scrub the board clean. You can check gauge accuracy by buying some resistors at Radio Shack. Both gauges are the same range:

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

The gauge wiring: The temp sender goes through the bulkhead connector, and this can become loose/ corroded, and the sender connector at the end of the wires may be corroded internally or even broken

Senders: Both must be good, and they can go bad. Make sure the fuel sender is grounded. The sender does not necessarily make contact with the tank, and the tank does not necessarily make good contact with the body.


EDIT. I don't remember for certain, I think your old 65 may have the voltage limiter inside the fuel gauge. If it does, you won't (obviously) find one externally, and the fuel gauge will have THREE terminals. This is because the 5V output of the voltage limiter is brought out and jumpered over to power the temp gauge.
 
If the lights go out and a jolt gets them back on, Lack of chassis ground is very likely all of your problem. Even the mechanical limiter for the gauges would suffer.
Those panels stampings have turned back corners that touch the dash completing the ground path or half asrsed anyway.
Easy panel to pull so dig in, fix the ground issue and see what it does.
I wont go into the possiblity or effects of current traveling your speedometer cable.
Good luck with it.
 
On speedo unscrew the cable from the head and remove the speedometer cable from the housing. After cleaning the old cable off, coat it lightly with wheel bearing grease of choice and without it touching any dirt from floor reinstall it back in housing. Might have to turn it some (lightly)when it goes inside transmission speedomter gear. Then reattach, HOWEVER with problems you have you will be pulling the dash part anyway for the other issues.
 
The speedo cable should be lubes with powdered graphite, like for locks. The grease can get hard in there and start to foul it, happens after long sits. Take speedo cable out and wipe all that green/gold stuff off it, that is old lube. Dump entire 1oz tube in the sheath.
 
Your cluster Vreg is built into the fuel gage and can't be rebuilt. However, you are better off upgrading to an external electronic one. Search "voltage limiter" and "Plymouth" on ebay. $30 w/ shipping from several sellers, with photos of how to install and disable your original one.
 
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