Voltage regulator queation

[Jack Innes]

I recently purchased an M38A1 in good condition. The previous owner replaced the "bread box" regulator with a solid state unit but just plugged it in to the original harness. The ammeter reads 0 as expected. I am aware that there should have been a different harness & a volt meter installed. My question is, has running with the ammeter connected for a hundred miles or so ruined the new regulator? Is there a way to test this?
Thank you for any input.

[Ben Dover]

You need a 5 Wire "Spider" to feed the #27 Circuit to the terminal on the Bat-Gen Indicator. The existing Voltage Regulator Harness circuitry is not equipped to feed the Bat-Gen Indicator, Tte off the two wires to the Ammeter, they are no longer needed. All 25 Amp Solid State retrofits need this done. You now have a trouble free charging system.
Adirondack Surplus has the spiders as do many of the Jeep parts dealers. Ask for one with Douglas Connectors.

[Jack Innes]

Thank you Ben for the speedy reply. I am to take it that the new regulator has not been hurt by running it connected to the old harness & the ammeter??

[Ben Dover]

No, nothing will happen, and you do not have to let your Jeep sit while you wait to add a #27 Wire.
Remember to always disconnect the Battery Ground while removing the Instrument Panel and or working behind the dash. I have seen a lot of long faces when the wiring harness insulation burns to a crisp.

[Jack Innes]

Thank you again Ben, Good news - quickly!! I am off to find a gauge & harness.

I am aware that 24v with a lot of amperage behind it is very unforgiving.

[Ben Dover]

Gauges with Douglas Connector are a bit harder to come by, the rubber (Packard) type are everywhere.

[bikeman]

No, nothing will happen, and you do not have to let your Jeep sit while you wait to add a #27 Wire.
Remember to always disconnect the Battery Ground while removing the Instrument Panel and or working behind the dash. I have seen a lot of long faces when the wiring harness insulation burns to a crisp.

Forgive me for this, but, wouldn't it just make sense in the first place to disconnect the batteries when working on ANY electrical?

[Ben Dover]

It always makes sense, but there are some who are not cautious for whatever reason. This has been hapening since 24 Volt M-Series Trucks have existed. The sharp edges od the dashboard opening make a good place for bare wires to find a ground. I have seen this dozens of times over the years.

[Jack Innes]

Found a volt meter & harness today - installed it as instructed - works fine!

I did find a connector attached to a right angle bracket with about a 5/16 hole in it hanging loose behind the dash. It looks like a ground but I am not sure. What could it be for & should I bolt it down? At present I have taped it to prevent a short just in case.

[Ben Dover]

That is the #85 Wire, it is live and is more or less an Accessory Wire and the one that you would use should you install the Hot Water Heater Kit. It is only Hot when the Ignition Switch is turned on. The connector with the little bracket is a safety cover, that's all. It hangs loose on the M-38/M-38A1 and the other 50's M-Series Trucks.