1864 PTO gremlin

[Rescue11]

I have tried thinking of reasons why my pto being engaged causes my headlights to turn on, but very dim. If i turn the light switch on while the pto is engaged, the pto cuts out. When the lights are switched on, they work well, but mowing after dark is about impossible anymore.

I thought it could be back feeding through a ground but that shouldnt kill the pto when the lights are turned on. Thinking there might be a small short between a wire in the pto ckt and light ckt... Based off some logical things i have thought about.

Any ideas?

[R Bedell]

Sounds like you are a partial circuit from two wires "rubbing" together.

Look at the PTO wire (brown) and the light circuit wire (blue) and see if there is a "rub" spot.

[ol'George]

Check engine to frame ground, also the headlight ground taking care to see that it is good also.
It sounds like it is back feeding a circuit, especially the lights being dim.
if no joy, it is going to take some tracing of the circuits during the malfunction.

[Shrewcub]

What they said!

I don't know if the 1864 harness is like the 2000 series but I had one of those open yesterday. All the grounds tie to a common splice in the middle of the harness.

My grandfather's 1863 developed a short in the headlight circuit and would blow the fuse. I just pulled the blue wire from the ignition switch since it doesn't now in the dark.

I'd start with a "wiggle" test of the harness, especially where it runs along side the engine.

[Berwil]

I like the bad ground theory. I think the headlight bulbs are enough resistance to act like a ground for the little bit of current the relay draws and keeps it pulled in. When the lights are turned on, it takes away the "ground" and the relay drops out. What part is not grounded well, I don't know, but I would start with George's recommendation.

Bill

[Sam Mac]

Gotta love the Cyclops wiring. This is how I usually fix them. Take the complete mess out and toss it in the trash then build my own harness. Unfortunately I can't share what I do.

[Rescue11]

Thanks guys! Gave me some other ideas to use. If all else fails ill go the Sam route.

[Frank1541]

My guess is that you have a bad key switch among many problems. I think that Sam Mac has given you the best advice. I was working on the wiring on my 1541 last fall and found that almost every wire was bad or going bad due to cracking insulation. It is set for a re-wire this spring.