240S - Gauge Problem

[rod330]

I recently purchased a 1998 MF 240S with less than 400 hours. I noticed the tach was working properly when I test drove it but foolishly didn't take the time to carefully inspect the rest of the gauges. The prior owner verbally confirmed they worked.

The oil pressure idiot light, fuel level and water temp gauges do not work. I don't know if it has a horn but does not work if there is one. Everything else works fine, including all of the lights and road flashers.

The manual references a single fuse block with six circuits. Interestingly enough, one of the fuses supports the "engine oil pressure warning light, fuel gauge, fuel tank sender unit, engine temperature gauge and brake lights". However, none of the six fuses were blown and I have continuity at each of the six fuses. Although not documented in the manual, I discovered two in-line 8A fuses wired into the large light switch. One is a yellow wire with good fuse and continuity. The other is a white wire that does NOT have continuity regardless of the position of the light switch. It appeared the original glass fuse was blown and I replaced it-- but still "no go" with the oil pressure idiot light, fuel and temp gauge.

I'm completely stumped. Any ideas / suggestions would be greatly appreciated! Thanks in advance.

 

[Agvg]

Bad ingition switch? You have a ingition position on it, not just start?

 

[rod330]

Bad ingition switch? You have a ingition position on it, not just start?

There is an ignition switch with off-accessory-start positions. In the "accessory" position, everything works as expected except for the oil pressure warning light, fuel and temp gauges.

I grounded the "+" side of both gauges. The fuel gauge needle moved to full as expected which indicates the gauge is working properly. Perhaps there's a faulty fuel sending unit. When I grounded the temperature gauge, nothing happens which suggests it may be a bad gauge. Both gauges have good continuity at the "+" terminal. The oil pressure warning lamp is a complete mystery-- no continuity whatsoever.

 

[HarryVanderpool]

It sounds like you have a ground problem.
From panel to frame, frame to engine; check ground path.

 

[Phillip w]

I wonder if at some point in time a voltage spike was sent through the system and messed up/blew a bunch of stuff. The in line fuses would suggest somebody has been tinkering around with you electrical system. The newer the tractor, it seems the more complicated things get. I have an allis Chalmers 185 and it had issues. The tachometer is mechanical. The alternator/charging gauge worked but nothing else. I never could get to the bottom of it and ended up bypassing and rewiring a bunch of stuff. I also had a 730 John Deere diesel that shorted across and sent 24 volts to everything. It blew everything, lights, gauges, etc. I don't know how complicated these newer massey ferguson compact tractor are, but if someone was tinker around with your elecritical system, that could well be the root cause of the problem. The challenge is going to be what is or got messed up. Hope this helps.

 

[redman135]

On the 240 the horn is noted for not working, even when the tractor lives in a dry shed. If no horn is an issue then I suggest you change the horn switch to a marine grade switch.
Electrically I can't help as the electrics were otherwise reliable.