[GeoffD]

Ok here is the problem, maybe someone can help.

1999 Ford F 350, 8.5' Fisher V-Plow installed in the Fall of 1998.

Headlights on the truck work fine, high and low beams. Low beams work on the plow, but not high beams. Just had this problem happen about 5 Mins ago during a truck check. Going to stick my mechanic on it tommorrow. However do any of you guys have any hints?

Geoff

 

[CT18fireman]

Probably that light relay. I would check all the connections first. I am not that educated on the new Fords as I only own the old style. I have heard of light problems with the Fishers though. Good Luck

 

[PINEISLAND1]

Same thing happened with my older Ford. I lived with it for a long time, then went through with dielectric grease and did every connection I could find, and lo and behold, it is fixed. I just assumed the guy wired it wrong on the install, because it was that way since new!

Headlight relay-grease!

 

[HYDROCLEAN]

Re lights.

Did hi and low work on the plow when it was first installed?
If it did check all wires and look at your relays. Make sure both relays are tripping over.
I was plowing last week and went to back up after the end of the run and my Fisher quit. Looked at the front of the truck and the plug came unpluged. Make sure your plugs are clean and then apply dielectric greese to all terminals.
If you still have a problem I could post a schematic drawing that might help.
Goodluck.
Drew

 

[Deere John]

Geoff - I've read about your electrical wizzard before, so I won't even speculate, but let us know what it is.

Ok, I'll speculate a cracked wire with corrosion in it. Second guess is a bad DP/DT switch.

 

[BRL]

I have similar problem with my Fisher Minute Mount. When I plug it in now the plow lights don't come on. Truck sits high so we've been using the truck lights but it would be nice to have the plow lights. Forgive my ignorance, but where do I find this light relay that you're all mentioning. Is it part of the area where it plugs in? Or somewhere else along the way? Is this a common Fisher part that I can order from the online plow parts suppliers? How do I know if it is broken or not, come to think of it? What & where is the DPDT switch? Thanks

 

[GeoffD]

There are no switches on the new min mounts. It is all a system of relays. Every thing worked fine up till tonight, so we have some sort of problem.

Plugs are greased and connect well.

The trouble is Fisher has like 2 or 3 types of headlight systems that have been developed after the release of the min mount system. The most complicated for the truck owner is the current system, the isolation module. However the Isolation module, or I-Force system is the easyest for the dealer to work on. I am not sure what system is installed on this truck.

My mechanic is going to start working on it tommorrow and see what he can come up with. I think it may be a bad connection. We haven't had any plow light problems for a real long time.

When I find out so guys will find out. It never hurts to ask around before ya start working on it, sometimes there is a really simple answer.

Geoff

 

[nsmilligan]

Geoff, 1st check to see if there is 12v at terminal 30 on each light relay. The one with green wire is for high beam.
If there is apply 12v to terminal 87 with white wire. If there 12v at the black or white wires in the plow headlamp connectors, then the black/orange wire in the plow harness is open repair the wire. If not check pin 6 in the 12 pin grill connector for 12v if not, that wire or you harness needs to be replaced The pin numbers start 1,2,3 etc from the top left hand pin looking at the connector, with the alignment bump on top. Pin 7 is at the bottom left. If there is power at pin 6 then the wire on the plow side is open.
I'll bet it is a connection problem at this pin.

Bill

 

[Stephen]

we had a problem like that on a '97 ford with a western uni-mount plow once. thought it was the plow setup, but it turned out to be were the regular headlights were hooked up, wouldn't allow the plow lights to work. On that ford there was a little black box, behind the truck headlights, where the wires plugged into. Straight from the factory this box wasn't sealed, the end where the lights plugged in was open and it was filled with corrosion from the road salt, dirt, etc. Once you figured out the problem it was a simple fix, as it was a common in stock part. This black box/connection thing could be the relay switch or part there of where the problem is. Worth a look anyways...

 

[GeoffD]

Well my mechanic was pretty sure he fixed the problem only time will tell.

Brought the truck in the shop with the high beams on, but no lights. Unplugged the connecting plug, and plugged it back in and lights came on. So he looked over all the conenctions and they looked good.

Truck back in service problem fixed as far as we know.

Geoff

 

[nsmilligan]

Goeff, my EZ-V is in it's 4th season, and I was having connection problems with the 12 pin connector on the grill. It was always kept well greased with dielectric, and the tension cap was always on, but I think the connectors are getting a little worn. I took a very small screwdriver and pried each of the pins a bit to spread them open. Be VERY careful break one and you'll need a new harness. Also I took a 9" rubber bungee cord and snap it around the connector to hold it tighter to the female connector, since I've done this I've had no problems. I think before next season I'll replace the harness, or at least kept the male side as a spare.

Bill