Plymouth Scamp amp meter simple bypass

1974 Plymouth Scamp Amp meter bypass on a stock car by adding just one wire.

[@vincemajestyk9497]

In the late '60's and early '70's the 'standard' base alternator was 37a for everything. Optionally it went up to 46a and then to 60a. I think '74 or '75 they introduced the 100a which was a 78a nominal alternator. The biggest reason they went to that was because of the heated backglass (rear defroster). I usually just run a parallel shunt wire from the alternator stud to the starter relay stud, 8ga or lower wire. It splits the path between the original wire and the new wire so the Amp gauge isn't going to read correctly. A Volt gauge will show more meaningful information anyway.

[@oldblueaccord2629]

Yes I forgot to add alternators have gone way up in amp ratings. Thats an important point!

[@windsor7584]

I'll give this a try on my 1985 Fifth Avenue. The ammeter has gone crazy and with air conditioning on (it's summer here in Australia now )it goes way over to the left and stays there. Even when a/c is off it shows a discharge all the time. This all happened only recently. I installed a new voltage regulator, then a new alternator that I already had , but the problem persists.Was planning on installing a new gauge if they are still available, but will give your idea a try first.

[@oldblueaccord2629]

I hate to say it but the gauge maybe melted. Its very common fail point. You may have to take the gauge out and tie the wires that are there together.

[@windsor7584]

@@oldblueaccord2629 Yes, you are probably right. I will have to get something sorted out, either way. Thank you for replying to my post.

[@straightrazorstevepublishi4899]

I have a 66 Dodge with original alternator. I'm new to this myself. My alternator has a blade connector and a bolt connector. Do I run the thick wire to the blade connector or the bolt connector? Thank you.

[@oldblueaccord2629]

With out looking at it I would guess the bolt connector. its the heavy duty lug on the alternator. I would look at an electrical diagram and make sure. Spade is usually for the voltage regulator.

[@pcterm2]

factory specs is 13.8 volts to 14.8 volts

[@robbrobb325]

So if i have a 300a alternator and use this method ill be ok ? Running a huge sound system in my 69 fury

[@oldblueaccord2629]

300 Amps? That sounds huge. Yes make sure you are using the correct gauge wire for your amp output and go straight to the battery! I would go multiple batteries before I would go that big on the alternator. Youll need a serpentine belt to run it.

[@jasonkaiser5150]

So your amp gauge don't work anymore?

[@oldblueaccord2629]

It just barely moves off center but still tells you if its charging or discharging. A voltage gauge is much better and safer.

[@windsor7584]

What about the wire on that alternator lug that is already there? Does the extra wire to the battery just go on to the alternator lug alongside the original one?

[@oldblueaccord2629]

yes the first original wire goes to the amp gauge the new wire you put on goes from the positive side of the battery to the large lug on the alternator. This helps protect the old small gauge wire from getting to much amps and overheating.

[@rogergorrell1849]

@@oldblueaccord2629 Thank you . This is very useful advice .

[@oldblueaccord2629]

Windsor i didnt answer your question fully. YES both wires can go on the large lug on the alternator so power still goes thru the dash like factory. Hope that more clear.

[@jeremyschneider8981]

Does this bypass voltage regulator and if so won’t my battery over charge?

[@oldblueaccord2629]

@@jeremyschneider8981 no sir