Resistor? revised!

I'm replacing my fuel gauge(speedo) and sending unit in the tank, and have read on other posts that they work on 5volts. What's the big relay looking thing that feeds the gauges with power? it has 12v feeding in and 12v out, if I hook to the gauge it pegs the full mark. With only 6v(test battery) it shows the proper fuel level in the tank. The temp guage is currently broken and disconnected. What size resistor do I need to put inline to reduce voltage down to around 5v from 12v. :hurrican:

 

See next message. These guys sell the resistor you need. I don't remember the p/n but it was about $3 plus shipping.

 

http://www.centechwire.com/catalog/accessories/zr2.shtml

 

finding out stuff

I searched several sites and found out that it is a mechanical voltage regulator. Supposed to regulator the power to around 5v for the gauges to work.
Mine is apparently not working, I like the resistor idea. I'm sure that my part is way more than the $3 resistor setup that the hyperlink showed me. I guess the 'ol 56 will stay in the garage unit I can order and recieve one.
Most info I found was for later model year jeeps. My gauge has two posts, not three as shown in their info.
Any other info is appreciated.

 

First, this system is very difficult to test outside of the jeep. It is easier to burn out a gauge or sending unit than it is to make them work correctly outside of the jeep.

If there is a unit bolted to the side of the speedo that connects to the gauges then you have the old style.

The new style and repro gauges have the regulator built into the fuel gauge - three terminals on the fuel gauge. It is very easy to hook it up, but because of the grounding requirements of the gauge system you can get some faulty readings - again, this is when you are trying to test outside of the jeep.

If everything is connected properly, you could check the fuel system by moving the sender up and down. You cn do this whilst the sender is out of the tank, but it is imperative that the rest of the gauge system be installed properly in the jeep.

You must have the gauges all grounded properly to avoid frying the sender.

Ground the sender housing, then turn on the ignition and vary the sender float to watch the gauge.

To check the temp gauge - ground the wire coming from the temp sender in the block and the gauge should deflect towards hot.

If you have a repro fuel gauge and a old style external regulator, then you can put the external regulator on ebay for someone who has an original old style gauge and wants to use it becuase you won't need it.

The electrics in the gauge system are not complicated, but they are unforgiving and damage is immediate if not connected exactly right the first time.

HJow do I know? I have burnt out more gauges and fuel senders than I really want to think about. I guess I'm a slow learner.....