Guage cluster wiring.

Majumbo

Anybody have a picture of the wiring on the Back of the guage cluster? Some of my wiring behind the cluster is gone, some the insulation has worn away or the end of the wire is gone. I traced some using the wiring diagram but still frustrated.

Also how is the guage cluster grounded? Through the mounting nuts right? Because my fuel and temp might not be working because I took it apart to fix the covers over the amp and oil lights. I gave another set but it might be toast as well. Ant way to test both gauges?

Thank you
Zach Webster

bob ward

The gauge wiring is straightforward. Power in goes to one end of the solid link that connects the fuel and temp gauges, doesn't matter which end, other terminals are wired to the senders.

You are right in that the earth of each gauge is via its fixings, and if the gauge is not earthed it won't read.

To test on the bench you need to connect your 6V battery to the gauge and use alligator clips or similar to earth the case back to the battery, connect a wire to the sender terminal and leave the other end hang in the air for the moment. The gauges work by measuring the electrical resistance of the sender, so by earthing the wire you have zero resistance and by not earthing it you have maximum resistance. If your gauge is alive, and they are fairly bullet proof, the pointer will slowly move from one end of the scale to the other as you earth and unearth the sender wire.

This is a very good read on the ins and outs of fuel gauges, its written on UK Jaeger gauges but all fuel gauges and their senders are essentially the same inside, this also applies to temp gauges that use the resistance type sender.
http://mgaguru.com/mgtech/electric/fg_01.htm

Walt-LA

Zach,

I've tried to attach a newsletter from the Red River chapter HET which has an article on the workings of the Hudson gauges from '51-'54. It may be too large to attach here. If it is send me a PM with an email address and I'll copy it to you directly. It is in .pdf.

WaltLA

It seems to be too large.

RonS

Zack, it might be a good idea to down load a wire schmatic. Do not forget that in 51 and on, Hudson added a voltage regulator to the fuel and temp gauges to drop voltage to, I believe, 5 volts.

Park_W

Zach, the grounding of the gauge cluster is really irrelevant. The two gauges are supplied with power via the ignition switch, with connections as described above, and the internals of the gauges are grounded by their sending units in the cyl. head and in the gas tank respectively.

Majumbo

Thank you. I have a wiring diagram it's just hard to read, that's not the problem, it's trying to figure out the rats nest under the dash. Park W yeah I just figured it out last night, only reason for the cluster to be grounded is for the dash lights. Walt la I sent you a pm

bob ward

Honestly guys, the system needs 2 earths for it to work, the gauge needs to be earthed and the sender needs to be earthed, fortunately the 2 earths normally happen by default through the mountings.

Walt-LA

Zach,

PM didn't come through. Try this but drop the HET

<HETmasonw@uab.edu>

Walt-LA