MF 135 gauges

SkyePN · Sep 22, 2020

Work continues, next is fixing the gauges that don't work.

Gas gauge - can I ground or supply 12v to a terminal to check if the needle works? Looks like the pink wire should be connected to terminal 4 on the voltage regulator, what's that supplying?

Gas tank sender - check resistance range?

Ammeter - doesn't work, going to clean up the terminals and check with multimeter

My light switch is just on-off, not sure if that's original and haven't checked if the gauges have lights or actually light up.

It looks like the gauge lights all run off the inverter, what voltage (dc?) is the inverter supplying?

Thanks

jtxn · Sep 23, 2020

If the fuel gauge is original you can ground the post with an alligator clip to the fuel tank or chassis and it should peg to "FULL" .

Setup your multimeter correctly and you can measure the resistance of the sender by moving the float up and down.

I have not purchased a replacement gauge. I believe they are 30-240 ohms.

If you have a 6" tank you will need an ADJUSTABLE sender that is listed for a 150 or 165 and only 5 of the 6 mounting holes line up. I plugged the empty hole with oil gasket sealer. This part is only available from AGCO. It's $100.

If you have a 9" (more common) tank you can purchase a new sender from this site.

If your ammeter does not work you should fix it first. Often times it goes oil pressure gauge>>ammeter>>rest of the gauges.

I haven't messed with the lights. I cut the wires out.

SkyePN · Sep 23, 2020

Thanks I'll check all that this weekend! Where do I measure the tank 6" vs 9"?

jtxn · Sep 24, 2020

(quoted from post at 11:31:23 09/22/20) Work continues, next is fixing the gauges that don't work.

Gas gauge - can I ground or supply 12v to a terminal to check if the needle works? Looks like the pink wire should be connected to terminal 4 on the voltage regulator, what's that supplying?

Gas tank sender - check resistance range?

Ammeter - doesn't work, going to clean up the terminals and check with multimeter

My light switch is just on-off, not sure if that's original and haven't checked if the gauges have lights or actually light up.

It looks like the gauge lights all run off the inverter, what voltage (dc?) is the inverter supplying?

Thanks

Take a tape measure and stick in the in fill hole.

SkyePN · Oct 4, 2020

Thanks, really helpful. Gauge is ok and sender is open circuit. Tank is 6" so I'll look it up at AGCO as you suggest.

Ammeter was passing current but was all rusted up due to condensation. Managed to get it apart and let it soak in penetrant, springs working now. Bench tested ok, will reassemble and stick it back in tomorrow, better than nothing.

It's a rats nest of cut and spliced wires behind the dash. Figured out my battery drain too, the field terminal on the alternator is always hot.

None of the wire colours match the manual, not sure if there was variation or if the whole thing is a hack job.

(quoted from post at 12:02:00 09/23/20)
If the fuel gauge is original you can ground the post with an alligator clip to the fuel tank or chassis and it should peg to "FULL" .

Setup your multimeter correctly and you can measure the resistance of the sender by moving the float up and down.

I have not purchased a replacement gauge. I believe they are 30-240 ohms.

If you have a 6" tank you will need an ADJUSTABLE sender that is listed for a 150 or 165 and only 5 of the 6 mounting holes line up. I plugged the empty hole with oil gasket sealer. This part is only available from AGCO. It's $100.

If you have a 9" (more common) tank you can purchase a new sender from this site.

If your ammeter does not work you should fix it first. Often times it goes oil pressure gauge>>ammeter>>rest of the gauges.

I haven't messed with the lights. I cut the wires out.

MF 135 gauges

SkyePN

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jtxn

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SkyePN

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jtxn

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SkyePN

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