# Truck dies when plow is raised.



## srl28 (Jan 2, 2006)

Got a 1995 Silverado 2500, has dual batteries setup by the previous owner and a 7.5" Unimount plow off the front. Problem is, is that recently when you go to raise the plow, unless youve got your foot holdin the accelerator down some, the truck looses power and dies. Starts right back up again without a problem. Seems like the plow lifting is too much for the truck. Any ideas on what it may be? Alternator is brand new, and heavier than stock, both batteries seem fine and the battery gage in the cab reads that theyre fine, until you lift the plow that is, then it drops way down and the truck dies.


----------



## ahoron (Jan 22, 2007)

load test the batteries. could be bad motor on plow


----------



## mkwl (Jan 21, 2005)

How far down does the meter drop? Is it in the "red" zone? Did you just buy this plow from another guy in Sparta?


----------



## Mr. C (Sep 15, 2009)

I had that happen. Turned out the red power cable insulation had worn / melted the insulation and had a ground. I am guessing that the bit of corrosion at the battery, plug, motor all added resistance and led to the cable overheating a bit. I replaced the cable and all was good again.


----------



## srl28 (Jan 2, 2006)

Bumping this to the top, we still havent figured it out. Replaced the plow motor today, and although it seems to lift a little better it still bogs down and shuts off. Or bogs down real bad and takes its sweet time lifting. So....Solenoid? Batteries? there are dual batteries on the truck btw, if that helps. Alternator is new and heavier than the original


----------



## RichG53 (Sep 16, 2008)

Check the pump may be stuck valve.... How does the different motor sound when you raise it???? 
Strong or is there difficulty trying to raise the plow....


----------



## Thermos017 (Dec 16, 2009)

srl28;909936 said:


> ... Alternator is new and heavier than the original


how much heavier than the original? are we talking 120A or 200A? if you read the info on the dual battery thread there are posts about the big alternators not charging as much at idle. if you have the old alternator (if it still worked) install it and see if the truck still dies. my suspicion is entirely in the charge. check all charge wires as well. may need to upgrade small wires, or replace aged wires. if that doesn't help i'd suggest going to a battery isolator. you may not have both batteries running the plow with an isolator, but you won't have the truck running on both either. that means when the voltage drops on the plow battery, the truck battery will maintain charge and keep the truck running.

If you have an isolator already, it's probably garbage. it should keep the aux bat from drawing on the main. when you install an isolater you have to remember, there are different amp ratings on them. if you put a 120A isolater on a 160A alternator, you'll fry that isolater the first time you put a heavy load on the battery (i.e. lifting the plow in freezing weather). once the isolater is fried it's like not having one at all and it will cause everything to draw from both batteries rather than one.

if you have an isolater they are simple to test. with the key off, test continuity from the alternator post to each battery post. now swap leads and test the flow from the battery post to the alternator post. you should only have juice flowing to the main battery, not away from it. also you can do a voltage test with the truck off. the voltage of the main battery should only read at that batteries post on the isolater. the voltage of the aux bat should read at that batteries post, and depending on the isolater model, possibly on the alternators post of the isolater.


----------



## srl28 (Jan 2, 2006)

Thanks for the info there! Tons of great knowledge and info, took some time for us to sort thru and try, and still nothing. 
Replaced the plow motor- nothing
Cleaned and reconnected the battery terminals/wires/etc-nothing
Checked batteries for proper current and charge- nothing
Alternator is new and working as it should- nothin there either

So I'm back to square one and really need to figure this out asap cause I'm about ready to set the truck ablaze and call the insurance company and play dumb, just kidding but I'm at my wits end with this one.


----------



## mycirus (Dec 6, 2008)

What is your truck idling at? Is the Alternator the right one? Is it doing it all the time? I know when I warm my truck up I am down on power till I drive around a little bit.


----------



## srl28 (Jan 2, 2006)

Nope, thought of that too. Its right from the start, could drive around all day and it still does it. And it fires right back up after it dies, no hesitation. Truck is idling just under about 1k rpm last I remembered, could be wrong but I know its nothing out of the norm


----------



## mycirus (Dec 6, 2008)

Well I am outta ideas unless you could get a little bit smaller pulley for the ALT to see if that keeps your power high enough.


----------



## chp (Oct 22, 2009)

Check your ground from cab to frame I had the same problem with my 1990 k1500 Dealer could not find the problem and during some routine maintenance i found that the factory ground starp had rotted off. I replaced it with a larger one and have had no problems since


----------



## B&B (Nov 4, 2006)

Clean/replace the cab to engine ground cable. Fixed many with the same issue as yours by doing just that.


----------



## 2COR517 (Oct 23, 2008)

B&B;932414 said:


> Clean/replace the cab to engine ground cable. Fixed many with the same issue as yours by doing just that.


When replacing those ground straps, what's a good size cable to use? Is a #4/#6 battery cable overkill?


----------



## B&B (Nov 4, 2006)

There's really no such thing as overkill on a ground lead, the bigger the better. But for a cab to engine ground a nice section of 6 gauge is plenty adequate.


----------



## srl28 (Jan 2, 2006)

Silly question maybe but since its about 15 out and I dont feel like spending more time than I need to out in the cold, where would the ground cable you speak of be located on the truck? 1995 silverado 2500 reg cab long bed


----------



## B&B (Nov 4, 2006)

Some were on the rear upper portion of the engine and span over to the firewall and others were on a bell housing bolt. Honestly I'd simply add another one instead. A couple minutes and you'll double the ground path, plus you know the cable is in good shape internally.

While you're in there also check the small ground wires on thermostat housing. Those will also cause a stall condition if in poor shape as the one is the main ECM ground.


----------



## Thermos017 (Dec 16, 2009)

B&B;932479 said:


> There's really no such thing as overkill on a ground lead...


couldn't have said it better.



2COR517;932470 said:


> When replacing those ground straps, what's a good size cable to use? Is a #4/#6 battery cable overkill?


I recomend using a 1"+ braided ground strap for the engine to firewall/frame. using an actual ground cable, there will be a greater potential over time for the wire to wear out at the terminals and brake off. the ground straps are more flexible and designed to take the constant rocking of the engine on the frame. btw, this rocking is a lot worse in a plow truck, as you go between drive and reverse a helluva lot more than regular drivers do.



B&B;932533 said:


> Some were on the rear upper portion of the engine (passenger head to firewall) and span over to the firewall and others were on a bell housing bolt(also passenger side, from the same bell housing bolt that holds the trans dipstick tube). Honestly I'd simply add another one instead. A couple minutes and you'll double the ground path, plus you know the cable is in good shape internally.
> 
> While you're in there also check the small ground wires on thermostat housing. Those will also cause a stall condition if in poor shape as the one is the main ECM ground.


again all good info. also, if you add a strap instead of replacing the existing, there is a great location at the front passenger side of the block, and an existing bolt on the frame direclty to the side of the bolt on the block. they are right about level with each other (at the top of the frame) and maybe 6-8" apart. the one on the block may actually have your battery to block ground attatched to it already. i have added a ground strap to that location, as well as 1/2" straps from frame to cab, and frame to bed. the last two aren't always necessary, but i figure better safe than sorry. to add all three you're looking at less than $20 at napa.


----------



## TheEquineFencer (Dec 19, 2009)

Do some testing with a meter.Check the battery voltage during operation. Then put a meter from the Negative post on the battery and the other end to the engine block and see if the meter goes above 1/2 volt when you run the plow. Then try from the plow motor to the negative post. If it goes above 1/2 volt you either have a bad ground or a bad cable. It works the same way on the Positive cables. This checks for "voltage rise" on the circuit.


----------



## TheEquineFencer (Dec 19, 2009)

I just used this method to check a hydraulic lift motor for a guy yesterday. It would click but not run. I put my meter from the chassis to the pump motor ground itself, the frame of the motor, and tried to start it, the meter went to 8VDC. The mounting bolt holes were corroded, cleaned the mounts and it worked fine, he had checked the voltage from the chassis to the solenoid and read 12VDC and was about to go buy another $500 pump, My neighbor sent him to me to check it out before he bought one, told him I could fix anything.


----------

