MF 165, Charging & fuel gauge problem

[Upland Cattle Dog]

I have been reading your replays & I must say a lot of people know a great deal about MF tractors but I do have a problem with my MF 165 & maybe you all could help me if your have a little time?
Long story as short as I can, it's a MF165, Serial # 9AI9I42I; it has a GM alternator with the volt regulator under the dash/gauges. When I got this unit it never did charge & the fuel gauge never worked. Just within the past few weeks I took off the hood & replaced & painted a number of sheet metal items & was able to look at the wiring & tank gauge /sending unit better. I checked the alternator & regulator & they tested good, I could not see any damage wires or cut wires, started testing the wires & gauges to see if one is shorted out, but nothing worked. Than I took off the sending unit line to the tank & grounded it to see if the fuel gauge would work & it did not, but when I but a jumper from the battery to fuel gauge it worked, so did the Ammeter & the alternator started charging.
Whatç—´ going on? The fuel gauge only has 2 wires to it one pink one going to the volt regulator & the other going to fuel sending unit.
Could it be I have the wrong regulator on it/? If so do you know what the correct one would be or a name brand & part number of one that would work?
Thanks for you time.
John

 

[Farmwithjunk]

There is an oil pressure switch on the base of the oil pressure gauge. It senses oil pressure once engine is started, then completes circuit to allow gauges to receive power, as well as "exciting" the alternator. I've chased gauge problems 'til the cows came home and not found the solution until I changed out that switch. You might take a look at that for starters.....

 

[Upland Cattle Dog]

Thank you, didn't even think about that or even looked at it.
Acts like a light switch, I'll take look at it this evening when I get back in & tell you if we have a winner. John

 

[Farmwithjunk]

Well....It remains to be seen if that's the problem, but I'd ALMOST be willing to bet on it. Every one I've every ran across that had failed, the bottom had rusted away. (where spade lugs for wire connections are located) You'd think they'd have made stuff like that to last longer than 40 or 50 years.....

 

[Upland Cattle Dog]

Well, used a jumper wire on the oil pressure switch & according to the Ammeter the alternator is a charging.Yea! but the fuel gauge is not working. I didn'nt have much time to really look at it this evening, I just need to go back & take a better look. I'll follow up in a few days unless you may have another ideal.
Thanks for your help

 

[EE_Bota]

I'm watching this thread because my best bud has a 175 diesel. Not sure if they are similar, but I try to learn as much as I can about M-F.

 

[Farmwithjunk]

Well, used a jumper wire on the oil pressure switch & according to the Ammeter the alternator is a charging.Yea! but the fuel gauge is not working. I didn'nt have much time to really look at it this evening, I just need to go back & take a better look. I'll follow up in a few days unless you may have another ideal.
Thanks for your help

If it's an original OEM fuel gauge, chances are it's shot. They didn't work very long, nor were they notoriously accurate.

 

[Farmwithjunk]

I'm watching this thread because my best bud has a 175 diesel. Not sure if they are similar, but I try to learn as much as I can about M-F.

The entire DX series (135, 150, 165, 175, 180) was VERY similar. Especially so with regards to gauges/wiring/charging system.

 

[jrmcdona]

Hi, Does anyone have a picture of this switch? I have a 71 MF135 Diesel with an alternator and the battery is not charging up while running.

Thanks!

 

[midwesternhayfarmer]

Hi, Does anyone have a picture of this switch? I have a 71 MF135 Diesel with an alternator and the battery is not charging up while running.

Thanks!

It's on the last picture under the dash on the thread Massey Ferguson 135 electrical woes that someone already pointed out in your original thread.