Electrical wiz I'm not...

I have installed the second, replacing the first, Carl Walck instrument cluster for my '69 CJ5. The speedometer reads 10-12 MPH fast (by GPS verification), the oil pressure idiot light won't go out (I have an auxiliary gauge installed), and the temp gauge is inop. Suggestions? Any and all help is appreciated.

 

Speedo calibration relates to tire size and/or axle ratios. Did your original unit read correct?

If it was also reading fast, and your new unit is good, then it suggests the tires are smaller than the speedo is rated for, or the differential gears are a lower ratio. The general fix in most vehicles is to swap out the driven gear at the transfer case for one with the correct number of teeth. I'm not sure about availability for your jeep, even used... http://www.earlycj5.net/forums/show...tion/page2&highlight=speedo+gear+part+numbers

Both the oil light and temp gauge could be bad sending units - assuming your fuel gauge is reading correctly.

 

On the oil press idiot light, the light is connected to the oil pressure switch which is just that (a switch). It is either pressured ON or no pressure OFF. When the oil pressure reaches about 6 PSI then the diaphragm switch is pressured OPEN and the light goes out. You may have the wrong switch or it is faulty. Check it with a VOM tester. (volt/ohm/meter) Temp gauge= This sender unit is a variable resistive device. Warm engine=73 ohms warmer engine=36 ohms approx op temp=13 ohms hot engin=9 ohms. If you remove the wire from the temp sender and with the ignition "ON" you can ground the temp wire to the eng and the gauge should climb to "H".

 

​Thank you Gentlemen.