Replacement Speedometer Wiring

I had bought a used speedometer off ebay that looks identical to the rusted disintegrating one in my 1970 CJ5- it shipped from Canada if that makes a difference. I restored the new speedo and went to install it yesterday. The problem is my old speedometer has 3 connection posts coming off the back of the fuel gauge and the new one only has 2- the one for the hookup from the sender and the one that is bridged to the temperature gauge. I have 3 wires left and no place to connect them (I'll have to look again but I think one is power, one is from a cluster bulb and cant recall the third). Here is a pic of the 3 wires on the third post on the fuel gauge of the old speedometer that the new one is missing.



Any ideas how to wire it up with one less post? I am not necessarily the best with schematics. Thanks-

Chris

 

Maybe this will help.

 

Did you get a CJ speedometer, or did you maybe get a pickup or wagoneer speedometer?

 

Thanks for all the links. Will start looking through them. Here are pics:

Original:



Replacement I cleaned up front:



Back of the replacement- nothing looks tampered with:

 

I am thinking this is one . that maybe takes the external voltage regulator . been awhile seeing one

 

I don't have any help on the wiring but that cluster looks awesome.

 

Does a 6V cluster need a separate regulator? I know that the gauges will work when given 6V instead of the nominal 5V that the manual specifies. FSJ owners have replaced the internal regulator on the 12V cluster with both a 7805 and a 7806 chip (5V and 6V resp.) with equal success.

That said, the gauges won't function unless there is a circuit ... so the two wires shown are not enough to make the two gauges work. Check the bulb markings to see if they are for 6 or 12 volts.

I would take the gauges out of the cluster and test them on the bench. Many wall warts (transformers that plug into an outlet) for household devices make 5V DC... I use discarded wall warts routinely for little projects. Or you can string together 3 or 4 D cells, or use a 6V lantern battery. Not difficult.

 

Huh. I presume this means all the 6V systems used a K-S (King-Sealy?) cluster.

 

Regarding the faded condition of the original gauges, I expect that some Armorall on the gauge faces will darken them quite a lot. You can buy little bottles of fluorescent red or orange paint at the art supply store, and repaint the needles. If they function, use them.

 

IIRC the later gauges clearly say Stewart-Warner on them. A little disassembly might be enlightening.

 

The gauges in both units are Stewart-Warner. No chance of reusing the old ones, the unit had been full of water and everything rusted to the point of falling apart- including the posts on the back ripping right out trying to turn the nut on them. I do believe everything is 12V but thats just an assumption.

I did test the new temp gauge with a 9V battery and it moved just find. Dont have the means to test the new fuel gauge.

I assume the 1970 original cluster is slightly newer than the replacement, as I did notice one of the gears in the speedometer that turns the odometer had changed from metal on the replacement to plastic on the 1970 one. The face of these is somewhat unique- not sure how many years they made that style, but cant imagine the replacement cluster is that much older than the 1970.

 

back of a 55 unit . don't know if this will help you or not

 

Twin2- thanks. Is that a voltage regulator attached to the positive side of the fuel gauge?

 

sure is. I believe it is a 5 volt regulator.