450B - Need Electrical HELP!

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cordlesscarpenter
1010 crawler
1010 crawler
Posts: 265
Joined: Mon Jun 17, 2019 3:36 pm
Location: Southeast Indiana

450B - Need Electrical HELP!

Post by cordlesscarpenter » Sat Jun 04, 2022 9:24 am

Ok guys, I need some electrical help.

I swapped out the electrical sending unit style gauges for engine temp and oil pressure for mechanical gauges and I also swapped out the ammeter because it was part of that kit I got from NAPA so why not right.

Now, the machine won't start.

Without pushing the start button, just turning the key I got a big click, the ammeter freaked out, maybe a few more clicks then I turned the key off because I freak out a little when electrical stuff isn't working right.

At first I thought the new ammeter I installed must be bad since the other two gauges are mechanical. So I swapped the old ammeter back in and had the same exact response from the machine.

To help you help me... when I swapped in the mechanical temp and pressure gauges, I connected all the sending unit wires back to the same posts on the new gauges that they came off of from the old gauges and the other end I wrapped in electrical tape. I thought I better put them back where they came from in case one of those wires was a jumper completing a circuit for something else. Should I be doing something else with these wires?

The batteries are disconnected anytime I deal with electrical.

The batteries are reading 12.4v

I didn't touch anything else electrical

What am I doing wrong here?

Thanks in advance!!

Jim B
350 crawler
350 crawler
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Joined: Sun Nov 05, 2017 11:36 am
Location: western Maine

Re: 450B - Need Electrical HELP!

Post by Jim B » Sat Jun 04, 2022 10:54 am

If I am understanding what you did. Other than if a mechanical gauge is backlit (or on that is part of a shutdown system like a Murphy gauge set up) for night operation it should not have any wires hooked to it. I would say start by unhooking the wires from the gauge posts and taping the ends of them up and see what happens. Posts on mechanical gauges are generally for mounting, not insulated, and will create a ground for any wire hooked to them; effectively grounding your ignition switch out.

cordlesscarpenter
1010 crawler
1010 crawler
Posts: 265
Joined: Mon Jun 17, 2019 3:36 pm
Location: Southeast Indiana

Re: 450B - Need Electrical HELP!

Post by cordlesscarpenter » Sat Jun 04, 2022 11:34 am

Very good insight Jim, thanks so much! Makes sense.

I'll give it a go to see what happens and report.

BTW the new gauges are indeed backlit but I just taped them up for now, as you know, I am not good with electrical stuff and the last thing I want to fool with is figuring out the best place to attach all the illumination wires. Plus they would do nothing but create an even bigger mess behind the dash than there already is. Don't need to give the mice more things to chew on :wink: yet anyways

cordlesscarpenter
1010 crawler
1010 crawler
Posts: 265
Joined: Mon Jun 17, 2019 3:36 pm
Location: Southeast Indiana

Re: 450B - Need Electrical HELP!

Post by cordlesscarpenter » Sat Jun 04, 2022 1:15 pm

Jim, you're my hero of the day!

Happy to report she fired right up after disconnecting and taping up the ends real good. The mechanical gauges are reading like they should with no leaks.

Looking at the old gauges, you were totally right, like usual, they were insulated posts, both at the gauge as well as the mounting bracket itself. Learn something new every day! :D :D :D

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