Ammeter to Voltmeter Conversion -- Existing Wire Question

[mrmolding]

So I've been doing lots of reading before I posted this and I found a few examples where people described connecting the wires that connect to the ammeter under the dash and shrink wrapping it. But I've also read where someone also rerouted the ammeter wires at the bulkhead or made a modification since that current is still needed to power other things in the dash. Again, I am new at this. So here is my plan:

1. I have a new Dash Harness from M&H.
2. Going to get Redline Gauges to do the voltmeter conversion. I actually live 15 miles from them and took my cluster to them to talk details. But, it will be something like 8 weeks since they are busy. Lots of free time to work on car while I wait.
3. Got a charge wire with a fuse link from Crackedback a few years ago for another car that I never installed, so I'll use that from alternator to starter relay.

Here is my question: Does it matter that there are still ammeter wires running through the dash? Is there an additional step beyond tying the two ammeter wires together and leaving it at that?

Since I have everything out and I have done many other types of electrical wiring, I'm not worried about running new or re-rerouting wires/making connectors/etc.

Thanks in advance for any advice or ideas.

 

[VFilms]

Don’t know if this helps, but I just installed a volt meter on my ‘66. According to the wiring instructions I simply ran it off the switched (run not start) side of the ignition. The other side of the gauge just grounds under the dash. I did not touch the existing amp meter wiring.

 

[mrmolding]

Don’t know if this helps, but I just installed a volt meter on my ‘66. According to the wiring instructions I simply ran it off the switched (run not start) side of the ignition. The other side of the gauge just grounds under the dash. I did not touch the existing amp meter wiring.

Thanks! My real issue is if the wires are susceptible to fire with a larger AMP alternator even after combining them and leaving them in the dash -- is just combining the wires together and leaving it under the dash an acceptable solution? In time, I might want to add AC, EFI, and a decent stereo since I can't relieve the youth without tunes. I used to drive and love these cars and a few modern comforts are welcome.

 

[VFilms]

Thanks! My real issue is if the wires are susceptible to fire with a larger AMP alternator even after combining them and leaving them in the dash -- is just combining the wires together and leaving it under the dash an acceptable solution? In time, I might want to add AC, EFI, and a decent stereo since I can't relieve the youth without tunes. I used to drive and love these cars and a few modern comforts are welcome.

Sorry but I’m not comfortable giving advise on that. Perhaps someone here with a more professional electrical background/experience can help. Good luck.

 

[diesel_lv]

Read this, this how I did mine after Redline did my gauges. I printed it out and kept it next to me as I followed along. I used 10ga wired to pass through the bulkhead and the corresponding fusible link.
http://www.madelectrical.com/electricaltech/amp-gauges.shtml

 

[mrmolding]

Read this, this how I did mine after Redline did my gauges. I printed it out and kept it next to me as I followed along. I used 10ga wired to pass through the bulkhead and the corresponding fusible link.
http://www.madelectrical.com/electricaltech/amp-gauges.shtml

Thanks!!! That looks like my answer -- changing bulkhead wires, etc. Yup, Diagram A is what I was looking for!

 

[zyzzyx]

Go to Mad Electrical and look at the article on eliminating your ammeter so you don't burn down the dash.
I also purchased the headlight relay kit from Crackedback so I could take the load off of the system.

 

[diesel_lv]

2nd @zyzzyx on the headlight relays. Takes all load off the headlight switch and gives much brighter lights.

 

[mrmolding]

Go to Mad Electrical and look at the article on eliminating your ammeter so you don't burn down the dash.
I also purchased the headlight relay kit from Crackedback so I could take the load off of the system.

Crackedback said that I could just leave everything in place with his charge wire, but I just wondered if there was more to be done. Does the larger wire just take more of the load?

 

[mrmolding]

View attachment 1173730 Go to Mad Electrical and look at the article on eliminating your ammeter so you don't burn down the dash.
I also purchased the headlight relay kit from Crackedback so I could take the load off of the system.

I have his relay kit as well. Got it in 2018 and sold the car for this one in time. I was planning on using it on this one.

 

[zyzzyx]

Yes, and the 16Ga fuseable link protects the circuit.

 

[mrmolding]

Yes, and the 16Ga fuseable link protects the circuit.

So should I just use his charge wire and leave the rest in the dash alone? It would make life more simple.

 

[mrmolding]

View attachment 1173732 View attachment 1173733 View attachment 1173734 Yes, and the 16Ga fuseable link protects the circuit.

Did you just leave the headlight part of the original harness in place or hide it somewhere?

 

[Crackedback]

Crackedback said that I could just leave everything in place with his charge wire, but I just wondered if there was more to be done. Does the larger wire just take more of the load?

I thought I said you could if you chose to but that is not what I would do. Can you leave all the OEM wiring in place, sure. Not what I would do. I dislike ammeters, never run them, nor leave them connected in any car I have. My usual comment regarding the OEM charge path is leave it all in place if the bulkhead is in good shape, repair bulkhead as needed and connect the two ammeter wires to bypass.

I would bolt the two ammeter wires together with a machine screw and nylock, wrap it up and shrink tube it. If the gauge in the instrument panel is going to be a voltmeter, you have nothing to attach those ammeter wire to anyways. You can't just leave them disconnected or the black wire off the alternator. The power for the car is pulled off the black wire/alternator side.

Which car was the original kit set up for and what are you using it on now. There may be differences between the kits that need adjustments.

 

[zyzzyx]

If you look at the wiring drawing, you're making a continuous loop, with the 16ga. fuseable link protecting the circuit.
The charge wire goes from the alternator to the main lug on the starter relay, and this lug becomes your main Buss.
Between the headlight relays and the elimination of the ammeter, you basically fool-proof the system. Better design.
When you eliminate the spade connectors, the 10ga. wires go through the bulk-
head connector whole, and there's
no weak spot.

 

[MoparLeo]

The MAD electrical information was 2 parts.
Here is the second part of the article.
http://www.madelectrical.com/electricaltech/amp-gauges2.shtml

 

[mrmolding]

I thought I said you could if you chose to but that is not what I would do. Can you leave all the OEM wiring in place, sure. Not what I would do. I dislike ammeters, never run them, nor leave them connected in any car I have. My usual comment regarding the OEM charge path is leave it all in place if the bulkhead is in good shape, repair bulkhead as needed and connect the two ammeter wires to bypass.

I would bolt the two ammeter wires together with a machine screw and nylock, wrap it up and shrink tube it. If the gauge in the instrument panel is going to be a voltmeter, you have nothing to attach those ammeter wire to anyways. You can't just leave them disconnected or the black wire off the alternator. The power for the car is pulled off the black wire/alternator side.

Which car was the original kit set up for and what are you using it on now. There may be differences between the kits that need adjustments.

Original was 68 rr with ac. This one is 70 RR 383 bone stock. Have replaced or replacing all harnesses. Thanks again!!!
Updated to put in the listing of current car. Got it from another member after a lot of negotiation back and forth. Great member!
SOLD - 1970 Roadrunner | For B Bodies Only Classic Mopar Forum

 

[mrmolding]

View attachment 1173760 If you look at the wiring drawing, you're making a continuous loop, with the 16ga. fuseable link protecting the circuit.
The charge wire goes from the alternator to the main lug on the starter relay, and this lug becomes your main Buss.
Between the headlight relays and the elimination of the ammeter, you basically fool-proof the system. Better design.
When you eliminate the spade connectors, the 10ga. wires go through the bulk-
head connector whole, and there's
no weak spot.

Nothing better than pictures! Thanks!

 

[zyzzyx]

Courtesy of Mad Electrical!

 

[hunt2elk]

Don't know how much it really matters, but Mark at MAD Electrical has changed his recommendation as far as wiring a bit. He hasn't got around to redoing the website yet. He is saying a guy should run the wire from the alternator to the starter relay unfused, but instead add a fuse link to the smaller red wire going from the battery positive to the starter relay. He thinks this is far better than his previous picture shows.