67 Battery/Amp meter stopped working

[Donald H.]

Is there any way of testing the amp meter other than swapping out with another meter?

I think I understand the wiring and function. One wire comes to the meter from the battery (via connection at the solenoid) and one wire come from the alternator (via connection at the horn relay), and the meter shell is grounded.

From what I have read, the meter actually reads the voltage difference between the battery and the alternator. Can I use a volt meter and check between ground and each of these two connection, and should I expect to see voltage in each case? If I get voltage between ground and each of these connections, then I would assume my meter is bad.

I get absolutely no movement in the needle. I can turn the key to on and switch on the headlights and should see a drop to the negative side, but the needle says at zero, rock solid.




Thanks,

Don

[Donald A.]

Re: 67 Battery/Amp meter stopped working

Don, I agree with what you describe as the wiring and function. Yes you should be able check with a volt meter at each gauge post and see 12V, and if the car is running, there should be a slight difference (higher voltage on the alternator side). A common cause of gauge failure is corrosion of the terminals where the wiring from solenoid and from horn buss bar go through the firewall connector. Carefully detach that connector, inspect and thoroughly clean all of the contacts this may help. Also reports of corrosion at the gauge posts where wires attach, clean those. I have read that a low voltage test can help determine if the gauge itself is frozen/faulty. Remove the wires from the gauge posts (battery disconnected obviously) and using a 1.5V battery touch the leads from the battery to the gauge posts, you should see a small deflection, reverse the wires, deflection should move the other way. Good luck with your repair!

[Wayne W.]

Re: 67 Battery/Amp meter stopped working

Those gauges are rarely bad. 90% of the time it is bad connections in the bulkhead connector.

[Joe R.]

Re: 67 Battery/Amp meter stopped working

Is there any way of testing the amp meter other than swapping out with another meter?

I think I understand the wiring and function. One wire comes to the meter from the battery (via connection at the solenoid) and one wire come from the alternator (via connection at the horn relay), and the meter shell is grounded.

From what I have read, the meter actually reads the voltage difference between the battery and the alternator. Can I use a volt meter and check between ground and each of these two connection, and should I expect to see voltage in each case? If I get voltage between ground and each of these connections, then I would assume my meter is bad.

I get absolutely no movement in the needle. I can turn the key to on and switch on the headlights and should see a drop to the negative side, but the needle says at zero, rock solid.




Thanks,

Don

Don,

Here is an article on troubleshooting gauges:

http://www.lbfun.com/warehouse/tech_info/gauges%20&%20instruments/Troubleshooting%20gauges.pdf

Scroll down for the ammeter. I can't verify how good the article is, but maybe it will help point you in the right direction. Good luck!!!

Joe

[Donald H.]

Re: 67 Battery/Amp meter stopped working

Thanks Joe, I had actually found that article. Doesn't help much to trouble shoot, but does provide good description of the meter function and connections.

Don

[Donald H.]

Re: 67 Battery/Amp meter stopped working

I'm still having issues with my meter!! Here's what I have done:

Disconnected the connector at the back of the volt/battery meter and used a 1.5 volt battery and jumped across the meter terminals. The needle deflects the full scale either negative or positive depending on how I hook up the 1.5 volt battery. So I am now assuming the meter is good.

With the car running, I tested voltage at the terminals on the meter wiring connector. I get 14 volts at one connector and 4-5 volts at the other connector. Does anyone know if these reading are in the ball part of what I should see?

I hooked the meter back up and started the car the the meter needle does not move. I also verified that I had good ground at the gauge cluster and the meter housing directly.

I have one of the handy little battery and charging testers that plug into the cigarette lighter. Using it, the battery tested low, but that may be because it needs charging (I now have the charger connected for overnight charge). It tested 11.4 volts and the handy tool I have says it should test 12.6 volts.

This tool also check the charging system. With the engine running I'm seeing 12.2 volts and the tool guide says that proper charging system is 13.3 volts to 14.4 volts. The 67 Chassis Service Manual test says with a low battery the charging system testing will be 12.5 volts or less.

I'm trying to figure out the testing outlined in the Service Manual. It refers to a Junction Block (page 6Y-11 in the 67 manual) and connecting a volt meter between the Junction Block and the VR ground. I don't see a Junction block anywhere in the wiring between the horn relay, VR and alternator. Can someone tell we where to connect the volt meter? Is it perhaps the red wire on the horn relay?

If I can figure out where to connect the volt meter I'll try the Service Manual test procedure tomorrow.

BTW, I have one of the solid state VRs what has seems to work fine so far.

Thanks,

Don

[Wayne W.]

Re: 67 Battery/Amp meter stopped working

You should get 12 v on both of those wires. Go back and clean the bulkhead connector.

[Donald H.]

Re: 67 Battery/Amp meter stopped working

OK. I'll try that also. If that turns out to be the problem, would it be OK to use some dielectric grease when I put the connectors back together?

Don

[Leif A.]

Re: 67 Battery/Amp meter stopped working

OK. I'll try that also. If that turns out to be the problem, would it be OK to use some dielectric grease when I put the connectors back together?

Don

Absolutely use dielectric grease when re-assembling...doesnt take much and will last indefinitely.

[Joe R.]

Re: 67 Battery/Amp meter stopped working

I'm still having issues with my meter!! Here's what I have done:

Disconnected the connector at the back of the volt/battery meter and used a 1.5 volt battery and jumped across the meter terminals. The needle deflects the full scale either negative or positive depending on how I hook up the 1.5 volt battery. So I am now assuming the meter is good.

With the car running, I tested voltage at the terminals on the meter wiring connector. I get 14 volts at one connector and 4-5 volts at the other connector. Does anyone know if these reading are in the ball part of what I should see?

Thanks,

Don

Don,

To add to what Wayne said, it sure sounds like you have an open circuit (no connection). I would recommend disconnecting one side of the battery, then use an Ohmmeter to make sure all the connections are good, especially the bulkhead connector. Once it's all connected properly, then it's time to hook up the battery and give it the old smoke test!

From what I understand, the ammeter is really a very sensitive voltmeter. So, it should see close to 12 V on both sides, it is looking for a small delta voltage between the two terminals.

Joe

[Donald H.]

Re: 67 Battery/Amp meter stopped working

Don,

To add to what Wayne said, it sure sounds like you have an open circuit (no connection). I would recommend disconnecting one side of the battery, then use an Ohmmeter to make sure all the connections are good, especially the bulkhead connector. Once it's all connected properly, then it's time to hook up the battery and give it the old smoke test!


From what I understand, the ammeter is really a very sensitive voltmeter. So, it should see close to 12 V on both sides, it is looking for a small delta voltage between the two terminals.

Joe

Every time I reconnect my battery disconnect I'm concerned about the Smoke Test!!!!! I am making progress. I took the harness firewall connectors loose and using hand wire brush and dremel tool wire brushes I cleaned up the terminals. Put them back together with some dielectric grease. Now I'm getting 14+ volts on both sides of the harness connector at the meter. I have not reconnected the meter yet, I got side tracked with another project.

Hopefully this fixed the problem.

Don

[Joe R.]

Re: 67 Battery/Amp meter stopped working

Every time I reconnect my battery disconnect I'm concerned about the Smoke Test!!!!! I am making progress. I took the harness firewall connectors loose and using hand wire brush and dremel tool wire brushes I cleaned up the terminals. Put them back together with some dielectric grease. Now I'm getting 14+ volts on both sides of the harness connector at the meter. I have not reconnected the meter yet, I got side tracked with another project.

Hopefully this fixed the problem.

Don

Hi Don,

I'm betting you have fixed it!!! Please let us know your final results when you get back to it.

Good job!!!
Joe

[Donald H.]

Re: 67 Battery/Amp meter stopped working

Nope. I re-connected the meter, turned the key to on and no needle movement at all. I started the car and no needle movement.
So I guess its on to a new meter.

Don

[Harry S.]

Re: 67 Battery/Amp meter stopped working

Don, another test.

Disconnect the wires from the gauge. Use a small volt battery 1.5 or so. Connect with alligator clip on one side. Touch the other terminal for 1/2 second. if you do NOT get any movement either right or left the gauge is DOA. If the gauge moves then the problem is somewhere else.

[Donald H.]

Re: 67 Battery/Amp meter stopped working

I have done the 1.5 volt battery test and the gauge checked OK.

Here is what I did so far today. I again disconnected the wiring plug from the gauge. I connected jumpers to the two terminals in the wiring plug. Started the engine and I am getting voltage readings of 14+ plus volts at one terminal and 12+ from the other one.

I am restoring my 66 coupe so I took the battery gauge out of that cluster. I connected it to the two jumpers from the wiring plug and grounded the case to a good ground via a jumper connected to the engine. With the car running I get no reading with this gauge either. So I guess it isn't the gauge.

Any suggestions now?

I though I got the wiring harness connector clean at the firewall. And as I state, I'm getting good 12+ volt reading with the engine running at the wiring plug at the gauge.

I'm thinking that maybe I can bypass the firewall connection all together and take the gauge out of my 66 and jumper one terminal to the B terminal on the solenoid and the other terminal to the RED wire on the horn relay and ground the case. If I'm reading the wiring diagram correctly that is.

Don