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Turned key on, Display went off after a second, now it won't start

4K views 9 replies 4 participants last post by  shadetree 
#1 ·
2004 Rancher 400AT

I knocked the mud off of it after a ride today (using a garden hose) then let it sit for a couple hours.

Went out and turned the key on and the neutral light and display came on, but within a second they went off. Now I can't get the display or lights to come back on. It won't even attempt to start now either.

If I pull start it, everything works like normal, but the lights sort of flicker when the brake lights come on too.

I thought maybe it was a bad battery but putting jumper cables on it didn't help and my winch works just fine too.

I'm stumped.

Any ideas?
 
#2 ·
Forgot to mention that I also checked all the fuses in the fusebox behind the battery. I'm not sure if there are any other fuses for the display.

But since it works when you manually start it I doubt it's the fuse or a power issue.

I'm leaning towards ECM at this point. :icon_frown:
 
#4 ·
After thinking about it last night, I think I might know what it is.

I've also had problems with the oil temp light not coming on for a few seconds when you turn the key on.

From the factory service manual, it says to jumper a couple wires in the 34P ECM plug. I did and the light came on. At that point the manual just says to replace the ECM.

I also vaguely remembered a recall about dielectric grease for this plug. My plug had a little bit on it, but I added more. I made sure to cover each contact opening. I don't know what I was thinking but I should have known better because last night I remembered that dielectric grease is actually an insulator.

But I also rode it for 4 hours and probably started it 20-30 times yesterday and didn't have an issue until after I washed it.

I'm going to clean out the dielectric grease from the contacts (and put a little around the edge of them instead). If that doesn't work I guess I'll look into a bad ECM.
 
#6 ·
Hmmm.

Looks like I was supposed to initialize the ECM after unplugging it, is that right? Also you need to reinitialize it after taking the carb off?

I took the carb off months ago and didn't reinitialize it. I also didn't initialize it after I unplugged it.

Could that be part of the problem?
 
#9 ·
What's funny is I tested the battery with a voltmeter and before that I even hooked up jumper cables. The wire was disconnected back behind the battery so you couldn't even see it, LOL. Just by shear luck I noticed it last night.

Definitely a new one for me!
 
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