73 Ammeter is dead

[Gary S.]

Good morning to all. After we installed my neighbor's 454 and did all the test runs and drives I commented to him that I didn't see any movement in his ammeter. I can't find anything in the archives on this so I thought I would throw out this to my friends here. Here are the symptoms: 1. alternator puts out 14.7 volts 2. both poles of the ammeter are receiving 14.7 volts 3. battery is new and frshly charged

I suggested that perhaps the ammeter died. Do any of you know if they are repairable or even testable? I know I have seen ammeters in some of the various catalogs but are they exactly like his original 73 unit?

Thanks, Gary

[George R.]

Re: 73 Ammeter is dead

Gary: Check your connections under the dash and the harness area around your voltage regulator. I noticed my meter never moved from just slightly on the + side of the gauge when I would have the engine off and turn on the lights etc.

Last week I renewed my enigine compartment harness and now my meter works. But I had found several wires melted and open on the insulation (jackets) at the fusable links areas. These wires needed to be replaced.

It really helps if you have a diagram to read and trace you wires back to the meter with from the area I mentioned. Somewhere in my cars long history (67 coupe)someone did a lot of home made crimp on work with whatever color or gage wires they could find.

Good luck,grr#33570

[Gary S.]

Re: 73 Ammeter is dead

George, thanks for the reply. The first thing we did was to check all the connections at the alternator, firewall, and fuse box. All were good and all the fuses had 14.7 +/- volts. If both poles of the ammeter are registering system voltage shouldn't that also be an adequate check that the charging system is good? My 66 had a similar problem but I located my fault at the engine side of the firewall where there was a lot of corrosion between the male and female side of the plug.

Is there a check or test for the ammeter and is it rebuildable? Gary

[George R.]

Re: 73 Ammeter is dead

Gary:

Have your tried to hook up to the ammeter connector that attaches to the gauge and see what it's reading or even getting power to it?

My problem was the black and blk/white wires I found up by the voltage regulator and horn connections that tied into the orange wires were melted. If you can look in this area you will see some rubber disc or connections called fusable links, nothing more than a metal crimped piece of metal usually reducing the wire size say from #12 to #16 or so. You may have to peel away some tape but when I did that's when I found my hidden jury rig of melted wires. These rubber boots or disc are encapsulating the wires.

If you have the diagram use it and trace it back to the voltage reg/horn relay areas. Make sure you are getting power to the meter connection(tight fit). Just remove it and attach your meter to the plug in.

Also the fire wall has two plastic plug in connectors that feed to the various fuses etc. One side runs to the right side of the engine area to the starter and heater fan and the other comes off the left side that feeds up to the volt/reg,horn relay,parking lights,headlights & motors also the limit switches etc.

I've pulled my(snap in unit) and found as I think you said these to be corroded. Look for a bad connection there also like one of the pins being bent from the last inspection etc.Be caeful in this area as these pins are old and probably brittle from age and corrosion.

Or, if you have a local electrical shop near you just drop by and they can trouble shoot it in minutes for you as they should have the equipment available.

But if yo have a meter check the power supply to the ammeters connection with the engine off and running.

Good luck,grr#33570

[Gary S.]

Re: 73 Ammeter is dead

George, I took my multi-meter readings off of the back of the ammeter, at the two contact posts. Both were 14.7 volts. As I stated in the first part of this thread, we are getting normal system voltage up to the gauge, leading me to believe (perhaps in my electricl ignorance) that the gauge is toast.

Gary

[Bill Lloyd #33481]

Re: 73 Ammeter is dead

Yes you can rebuild the ammeter. First, Check the ammeter continuity across the back to terminals. You should have continuity there. If not, the wire windings are broken/metled. Take the instrument cluster out. Carefully drill out the rivets on the ammeter face from behind. The windings are around a plastic piece that houses a permanent magnet. Count the number of windings on each side. Next go to Radio Shack and purchase the appropriate coil winding wire and rewind the plastic piece.

OR

Send the instrument cluster to ZIP or Mid America, Etc. to have it rebiult.

Good luck

Bill 33481

[George R.]

Re: 73 Ammeter is dead

Gary:

Sounds like your right on top of the problem. If I got power as you have to the gauges connction and NO reaction from the gauge I'd think the same.I didn't see a ground wire only a black and blk/white wire on the 67 diagram to the meter.

You should have a black ground wire about a #16 that grounds to the voltage regulator housing also. The capacitor is only for the radio if you still have one.

I guess it's time to pull the meter and bench test it before buying another. I think there are several places that you can buy rebuilds from. Post if you need help finding one.

Goodluck,grr#33570

[George R.]

Re: 73 Ammeter is dead

Gary:

I was giving you wire colors and connections from my 67 so they may not be the same as yours. I don't know what the hell I was thinking of. But it sounds like you know what your doing as far as trouble shooting.

Good Luck,grr#33570

[Gary S.]

Re: 73 Ammeter is dead

Thanks to all of you. I will pass this on to my neighbor.

BTW, you would think that for all the advice he gets from me or from this board, he would join the NCRS. (Are you listening Greg? )

Gary