Plow Problems - Help?

I've got a Western 7 1/2' Pro Guard on a 92 Ford F250. Problem is, the plow drains electrical system. Battery is new. Alternator is 60amp (reman)just replaced for 2nd time in a year. Plow Electrical motor runs good and does not drain under no load (not hooked to pump). Hooked to pump, the plow angles and raises fine (angles a little slow to left - but not bad). However, within 10 minutes of use, electrical system will drain and truck will stall. You can get the truck to stall real quick if you angle the plow to one side and continue to angle it after its reached max. Alt meter in truck will drains from 12 to near eight everytime you angle and then recovers pretty quick to 12 but like I said extended angling or moderate to heavy use will kill the truck's electrical. We then have to jump start it and baby it (raise/angle in short bursts) - or park it altogether). Otherwise truck runs great - no problems with heater or lights draining system. HELP - Need advice. I think it may be the new alternator is bad. Others? MUCH APPRECIATED!

Chuck Smith

2000 Club Member
Bob is right. You need at MINIMUM a 70 amp to run a plow properly. I recommend at least a 90 amp myself. Also, a MINIMUM of 550 CCA battery, and I recommend a 1000CCA battery.
Naturally under no load, the motor won't draw too many amps.
In your case, you might try to plow with the headlights off when you can, and shut off the heater. That is, until you upgrade things.

Thanks! - That's sort of what I was thinking too. The battery is 1000cca and we've been plowing with minimal electrical (lights, heat, etc). I've got a 2000 Dodge with a Western (almost same set up) and I can be running every electrical accessory at full tilt - when I use the plow there the meter barely moves a hair. It's got a bigger alternator (80 amps).
I'm gonna put a bigger alt in the F250 tommorrow. I'll let you know - (of course I'll do this and they'll be no snow for the rest of the season - Murphy's Law). Thanks!

[Edited by Jason Pallas on 01-24-2001 at 12:04 AM]


Junior Member
Yes, I agree with Chuck. Definitely do not hesitate to go overboard with the alternator. I had the same problem last year and by installing a second battery it did not help at all. Just before last storm I had a new alternator built and the truck did not show the slightest form of a low battery as it previously always has.

GeoffD Veteran
The Ford dealer may be able to get you an alternator out of an ambulance. You will have to use the pully off your current alternator. The ambulance alternators put out a lot of amps, I think it is like 200 something.


Eager Beaver

Senior Member
I have a 97 ford with a trailer pulling option. Check to see what alternator was used for that option in that year. I have had no trouble with the problems you are having although I have on vehicles before this year of truck. in fact the battery is still the stock one that has never been replaced. Seems to me it is a 120 or so amp alternator.Good Luck


Open Ground

Check your electrical for an open ground, that is a definite possibility, You will need a multi-tester and some extra hands, check to see if you are drawing a load to your plow system even when it is not in use.... If so, you will have to do some electrical work....
If your going to a bigger alternator,go to a larger frame size.They actually put out near what they are rated for,and last WAY longer than a smaller frame alternator due to heat.The best one for a ford would be a large frame 100 AMP unit,with the external regulator.Rebuilders can get larger stators to bump them up over 120,and high output regulators,to raise the output voltage.This is the smae alternator used on the ambulance package,except it's doesn't put out as much.The ambulance alternator is rated at 200 amps,and they can be real expensive.Dual "v" belts or serpentine belts should be used on alternators over 100 amps.

I also have a Ram 2500 Diesel with the 136 Amp alternator,and dual 1400 CCA batteries,on it's fourth season plowing with a 9ft Western Pro (electric) extended to 11.5 Ft and it nevers gives up.I am also running 130 watt headlamps,6 strobes,4 roof spots,2 backup spots,and two tractor lamps on the salter.Can run everything all night,no probs.You might want to look at swapping on one of these dodge alternators.

DaveO Veteran
Current Draw


Few years ago a coworker was complaining about his voltage gauge dropping to around 8 volts while using his electric/hydro plow. I took an "amp clamp" which measures current, and checked it. While lifting the blade the motor was drawing ~50amps. When it reached the top, the current surged to 200 AMPS. Anytime the pistons bottomed/topped out, the motor drew 200 amps. This was a 6 ft blade on a TOYOTA.

Now you understand why a 60 amp alternator is too small. I also strongly recommend dual batteries. They supply the current hit, and then the alternator recharges them while the blade is not moving.

Get the highest output alternator and dual batts. End of problem.


TLS Addict
You should be getting close to 14 volts at idle not 12. Check and clean ALL vehicle AND plow battery connections. Get battery load tested. Its either your battery or your alt.

slplow Veteran
I had in my gm 105 amp alt and a 1000, cold cranking batt and still had problems keeping the bat up. 0n my dodge's they have 136 amps alts and the lights never even dim. So I would at least put 136 amp alt in your ford.
Thanks for all these great suggestions. Now I've got some new things to try out - Hopefully, all the advice from your experience will help me troubleshoot this and be rid of it for good. Will keep you all posted on the results -Thanks again for all the ideas and help!

Ok here's how it all panned out - the culprit turned out to be a bad electrical pump motor! Here's what really grinds me, usually I do most of my own mechanic work. I didn't have the time to work on this particular vehicle so I'd taken it to a couple mechanics that I respected. It's been a chronic problem truck for snow - but runs great for landscaping.
Anyway, last year I had the alternator replaced ($180) while we were putting a heavy duty radiator in the truck ('92 F250) to remedy a chronic overheating problem. Earlier last year - we replaced the battery because it tested bad ($100).
Then, this year, the chronic drain on the electrical system reappeared as soon as we hooked the plow back up for winter. After the vehicle stalled during a snow storm and had to jumped twice, I took the battery in to re-check it. It was bad, but they didn't have a replacement - so I end up shelling out another $90 to get a battery so that the truck can continue its route. I took it in to have the electrical system checked later - $80. The mechanic told me everything was OK and that the driver was probably overloading the system by playing the radio, running the heater on high and having the lights on. A week or so later, the problem reappeared and I took it back to the guy and asked him to look at it again with special attention to the plow (motor and pump) as I was sure this was the source of the problem. His solution: a new alternator $250 this time. Two days later, another snow - another stalling problem. Back to the shop - this time the guy puts a new battery in - another $100! When I asked him about the draw from the electrical motor on the pump, he assured me he tested it and the draw was normal.
Finally, sick of having to do two routes each time this truck breaks down, I take it to the Western dealer. They test the draw and its 300 Amps - twice the normal! I had big suspicions that it was either the pump or the electrical motor. But, not knowing how to test the draw and know how to isolate the problem between the pump and electrical motor if the draw was too big, I decided to take it to the experts (instead of troubleshooting it myself and risking finding out I was wrong durring the next snow storm). Here's the painful part,after nearly $800 in two years to repair the wrong things (don't treat the symptoms, treat the problem!),they charge me $140 for the electrical motor and another $165 (nearly 3 hrs labor) to put it in! What a rape - two bolts and two electrical connections - $165! That hurts - especially when I could have gotten the motor for $100 and installed it myself in 5 minutes.
Even after wasting $800 in paying these half-assed mechanics to misdiagnose and repair things that weren't the cause, I wouldn't have minded paying for a hour in labor and diagnosis. Man, time to shell out the $25 for the Weestern Mechanics Manual and install new batteries in my multi-meter!
Sorry for the long post - thought I'd let you all know how it turned out. Thanks for letting me vent.
The plow still moves a little slow - but doesn't draw nearly the amps. I was thinking of replacing the pump itself (as we've got a new one laying in the shop and I did find considerable metal shavings in the system after it ran dry once). Also thinking of taking the crossover valves out and cleaning them (never flushed/cleaned them after I found the shavings and cleaned the resevoir). Any tips on removing and cleaning these valves?
Please know - all your help and suggestions have been greated appreciated. Thanks!!!

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