[donnymccoy]

Hi, residential user here, experiencing an electrical issue. I've tried my best to search through here for a post(s) with my exact scenario but have not been completely successful. So, please pardon a new post - I also didn't want to hijack other threads for myself...

Issue
- No plow lights
- No plow activity
- No light on fishstick controller

Setup
- All new equipment
- Fisher dealer installed two seasons ago
- SD 7.5, MM2, FleetFlex, Fishstick, 3-port ISO, 2-wire
- 2015 Toyota Tundra (Peculiar light kit or something).

Symptoms
- Midway through this past season, connection of light harness yielded intermittent failures to work. Would wiggle the connection and it always would eventually resolve itself.
- End of this April, hooked up for one final plow: wouldn't work at all, no lights on controller, no lights on plow, nothing.
- Disconnected and parked until I could get back to it.

Current State
- Controller does not light up
- Nothing on plow works

My Steps
- Plow connected to truck - check
- Fuses close to ISO - check
- Fuses on solenoid/pump - check
- Ground on plow frame - check
- Ground at solenoid - check
- Voltage at solenoid (input side) - check
- Voltage at solenoid (output side) - negative (but makes sense)
- Voltage on battery cable to plow - check
- Voltage on light harness - check
- Voltage on fishstick cable - check
- Voltage at various harness connections, including switched acc
- Read through guides from @cwren2472 on google drive but couldn't find my specific setup

 

[donnymccoy]

It's hard to get into a local dealer due to their workloads, my scheduling and having to leave my truck with them. If someone is local and wants a consulting gig to help me out at my house, I'm interested ...

 

[Avalanche 2500]

OK I'll go First,
U may hit the nail on the head when u said "wiggle" Symptoms is it still under warranty ? /

 

[JFon101231]

Sounds like bad port A cable from module to plow lights. If it doesnt sense connection, lights wont flip over and controller will be dead. If you want to test theory, you can swap with known good or tap into the ground jumper between A and B/C and run it to ground

 

[cwren2472]

You say you have voltage at the fishstik cable - i.e., the little white plug under the dash? If that is true, then the problem is a bad ground somewhere between that plug and the battery.

Or the controller is defective

Which is addressed in the guides

 

[cwren2472]

Btw, it does sound like you have a bad lighting harness also based on the initial description though since the truck side is new(er) I'd suspect the plow side of the light harness rather than the truck side. In either case, you would not have power to the molex plug if that was the issue.

 

[dieselss]

- Ground on plow frame - check

Huh? Should be directly to the motor.

 

[donnymccoy]

Btw, it does sound like you have a bad lighting harness also based on the initial description though since the truck side is new(er) I'd suspect the plow side of the light harness rather than the truck side. In either case, you would not have power to the molex plug if that was the issue.

Sorry, everything is new related to the plow.

I just got back with electric cleaner and gave the light harness a good cleaning on both plug ends. I noticed that I have some damage to the truck side plug, on the outside of the end. I remember having ice buildup outside of the plug when connected one morning (kind of a snow/ice event one night in February). I cupped it in my hand to thaw it out so I could disconnect. I want to say I remember seeing this back then but honestly thought I was imagining the damage. It only appears to be to the rubber. I must have had some grease gunked on it earlier because had I seen it this clearly I would have mentioned it in my first post.

REALLY hoping this is not my culprit...

Picture should convey what I mean...

 

[donnymccoy]

Also, I was doing all my testing this afternoon with the key on but engine off. Would a bad ground drain the battery? I have NEVER had issues with this truck/battery until tonight.

 

[donnymccoy]

Sounds like bad port A cable from module to plow lights. If it doesnt sense connection, lights wont flip over and controller will be dead. If you want to test theory, you can swap with known good or tap into the ground jumper between A and B/C and run it to ground

I've checked the ground connector between A & B and it tested good. I'm thinking you actually meant in the two connectors on the iso module ....

 

[JFon101231]

If you had the lights on while you were doing your testing, that could have been enough to drain it also.

I'm having a hard time finding the pin-out for the 11 pin lighting harness to confirm which circuit it is, but it looks from your pic that the actual terminal was ripped out of the top left hole. See how there is no silver collar in the hole?

 

[JFon101231]

Bingo - that's your issue. Found a pic, which is plowside, so you have to flip it around. See pin I yellowed in...

 

[JFon101231]

@cubicinches is up in that part of NY I believe, perhaps he can ship you a new harness

 

[donnymccoy]

Bingo - that's your issue. Found a pic, which is plowside, so you have to flip it around. See pin I yellowed in...

View attachment 195324

So ... definitely a continuity issue in that plug but the metal shroud is still in there for pin 7. I tried to bypass that pin two ways. I jumped from vehicle ground to pin 7 on plow side by squeezing a wire inside the mated plugs. I also bared the black orange wire just outside of the plug (confirmed that point was a good ground) and tried jumping from there too. Neither was successful... so even though it looks like the truck side plug may be shot, it is not the only culprit.

 

[JFon101231]

1) I jumped from vehicle ground to pin 7 on plow side by squeezing a wire inside the mated plugs.
2) I also bared the black orange wire just outside of the plug (confirmed that point was a good ground) and tried jumping from there too.

The part that needs to see ground is the truck side plug. It feeds that back up that harness towards the module, crosses over that jumper plug to the B&C harness, and continues down that into the control harness continuing over to the battery harness, where it hooks up to ground. It isn't clear (to me at least) in #2 above if you did to truck side or plow side? Similarly, for #1 if you did it within the mated plugs but the truck side plug is junk its not going to help you as it won't make it upstream towards the module.

FWIW, these plugs have a high failure rate because they often get bent back and forth when people are disconnecting. Most times you can't see the damage.

 

[donnymccoy]

Hi, pardon my lack of response - had some client priorities. So the root cause (and only issue) was that as identified by @JFon101231. So, by using a replacement truck-side plug I was able to avoid a costly harness replacment. I used part #

63726 / 66431 Western Fisher Vehicle Harness Repair Kit 11-Pin Striker Steel-Caster Ice Breaker Pro-Caster

and determined the correct wire matings with a continuity tester. After heat shrinking and wrapping in new flex conduit, it's as good as new and the repair is completely sheltered in my grille. I'm including this information for the benefit of others like me who may not work with this equipment as much.

I'm thankful to all the replies here. Cheers to a great upcoming winter season. My neighbor said since so many green acorns are falling already that we (central NY) are in for an early and hard winter. Guess we'll know soon!

 

[donnymccoy]

Huh? Should be directly to the motor.

You are correct, that phrase stuck with me since other threads use that exact phrasing...

 

[JFon101231]

Glad to hear you got it figured out (and I win the prize for remote diagnosis LOL)

For what it's worth to any future followers, that harness repair kit is $80 at 20% off list and you have to modify. Agree much cheaper than a new 26357 for $160.
Another option, especially for those "non-handy", is to pickup a new full light harness kit for an older truck for $200. Use the 26357 and you can throw up the new headlight harness online for $100 maybe a little more so net net you are into the OEM harness for $100 and no splicing.