I'm new on here. I'm hoping with the collective experience on this forum, that I can get some further insight to solve my machines woes and get her back on her wheels again.

I hope that I didn't overlook someone else's post. If this is a duplicate, I apologize.

I have a 2005 ATP 500. I had an issue with my winch control, and in the process of putting the toggle switch back together, I pinched and shorted out one of the wires. I've repaired this original issue (even isolated it to ensure there wasn't something else shorted there) but now I have no power to the dash, let alone being able to start the machine.

At the ECM unit I checked and have power on the red wires so the fusible links appear to be ok.

I replaced the ECM unit, thinking that it may have gotten messed up, but that never solved my issue.

Here is what I'm seeing on the 10 pin connector to the ECM.

A Orange = 3.75v from ECM to ground
B Orange = 3.75v from ECM to ground
C Brown = continuity to ground
D Blu/White = 0 v from ECM but 2694 ohms to ground
E Red = 12.2 v (same as battery between terminals)
F Red = 12.2 v
G Red/White = has continuity to ground on the ACC side
H Brown = continuity to ground
J Orange/Black = 0 v from ECM but 2.3 ohms to ground
K Orange/White = 0 v

NOTE1: I have soldered in connectors on A, B, G & K to potentially isolate any short that may be occurring.

NOTE2: A & B tested with and without A,B, G & K being isolated with no difference.

I'm not sure why I'm seeing a reduced voltage at A & B. Is this the result of a short, causing a reduced power output?

I'm starting to run out of ideas on this issue and would appreciate any feedback that's available.

Thanks in advance.
Paul

 

Have you checked the ignition switch wiring and connector? Should have power to one wire constantly.Either a red or red/black depending on wiring for your model. If you don't have I'd check into the harness that it ties into to and also follow the ecm wiring to see if any wires are shorted/meted from the original problem.If you don't have the manual might be worth it for the schematic to help you trace the wiring.http://polaris-atv.brssm.com/2005-Po...ce-Manual.html

 

Thanks for the reply Old Polaris Tech. On the ignition switch connector "D" pin (orange wires from ECM module) are testing at 3.75 v. So there doesn't appear to be any voltage drop between the ECM and the ignition switch. I'm guessing that the voltage to the switch should be the same as across the battery terminals (12.2 v).

Does the ECM drop that voltage (from the ECM to the Ignition Switch) down in the case of a short somewhere?

I have soldered in bullet connectors to some of the wiring at the ECM so I can isolate sections of wiring harness to try and eliminate/narrow down the problem, but that doesn't seem to yielded any results.

I did trace out the wires previously and never found any deformed/melted wires, but that was a few months back. I'll take another look, just in case I overlooked anything.

I do have a service manual with the schematics handy.


Thanks,
Paul

 

Orange wire is the battery protection circuit,pins A and B, and responsible for lights and dash power according to an earlier manual I have,but doesn't show voltage reading. This may be the problem area you're having. Red wire from the ecm should show battery voltage on pins E and F which you show you have.Possible that as soon as you plugged in the new ecm it went into protection mode same as the old ecm if you still have a wiring problem elsewhere in the harness.

 

Sorry for the delay in responding.

Thanks for the feedback old polaris tech. I was wondering the same thing, so I've isolated each circuit to and from the ECM.

When I eliminated all other connections and just ran the red wires to the ECM and the Orange wires from the ECM, I measured 12.2 vdc going in (red wires) and 11.8 vdc coming out (orange wires). That 11.8 vdc maintains with the rest of the orange wiring harness connected.

As soon as I connect the ground (brown wire) my voltage out (orange wires) drops to 3.75 vdc (even with no wiring connected to the ECM out terminals). From what I can see in the drawings, the ground just connects to the frame, so there's nothing out of the ordinary with that part of the circuit. Testing the Red wire to the Brown Wire, I meter 12.2 vdc, the same as direct to ground.

I'm not really sure what to make of this.

 

Sounds like a short in the ground path of either the ecm or wiring harness,possibly both when you hook up the brown wire. Ecm as you probably know has all the solid state circuits along with the battery protection circuit,fan control, accessory power,etc all in one box. If you plug in the old ecm and it still does the same,no power to the ignition and lights,drops voltage when grounded,then a new harness might be best option if you can't track down a grounding fault. It's not much more than the price of the ecm for a complete harness.Better than pulling your hair out trying to find the problem as it can be in the wiring or connectors.

 

Thanks for the feedback Old Polaris Tech. Since I've already pulled all my hair out, I'll probably follow your advice and pickup a new wiring harness.

Thanks for your time, help and insight.
Paul

 

I've had to do the same thing on wiring harnesses and end up ordering new ones. Sometimes it's hard to trace every little problem that could be in the wiring,connectors,pins,soldered joints,etc.