99 & up 7.3L Power Stroke Engine and DrivetrainDiscussion of the 99 & up 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.
Hi guys, new member but been lurking for a while. I can't find any solutions for my electrical issues with my truck, so here it is: Last October the truck started acting stangely when starting. Gauges would flash and jump around, truck would crank, maybe start maybe not. If it did it would quit in seconds. Flatbedded to dealer (extended warranty). they found a corroded post on the fenderwall? The post had electrical cable on it but was corroded through. They didnt replace the post, just bolted the cable together. Fast forward to late November, getting cold. Truck starts but batts are getting real weak. I figure they are original, so I replace them both with 800cca. Starts great, for a few weeks. Batts gradually get weaker until truck wont start. Put charger on, starts right up. Something is draining the batts. Back and forth with dealer, jump start truck rest of winter. Dealer says bad batts, replace with new. No problem all summer of course. Now its getting cold, truck is starting to struggle to start. Was the post they removed a ground??? Is this causing batts to drain??? So yesterday i am getting stuff ready for winter. Hook up the Boss plow, hit the switch to raise and lock plow onto frame, sparks are flying back and forth between the truck-mounted plow frame and the plow. *** ??? I need some help here. Why are the batts slowly draining, and what would cause sparks between the plow and the frame?????? Thanks guys.
Dan
I'd suspect bad cables where that corroded post was. I don't know of anything like that on the fenderwell, except maybe the starter relay. If the post and connections were corroded, then the wire beneath the insulation may have also turned into green goo.
Sparks between your plow and frame sure points to a ground problem.
Good Luck tracking it down. Seems like the dealer would have discovered what was wrong instead of doing a modification of the factory installation.
Thanks Klhansen. My electrical knowledge is limited, will a bad ground cause the batts to drain? I just had the grounds on the block replaced when i had a new oil pan installed (yes, it rusted through and started leaking). The stealer had the truck for a week and couldnt find anything, or so they say. Looking at some other posts, I guess I will try to isolate where the draw is by pulling fuses with the meter hooked up. I also read that a bad alternator diode can cause the draw??? Had the alt tested at autozone, report said bad diode in alt. Dealer said alternator is fine. Oh ya, also when I start the truck the lights are dim (comparatively) then within about a minute they blink on brighter (glow plugs shutting off???). Could be a combo platter here of bad ground somewhere and bad alt???
Could be a combo platter here of bad ground somewhere and bad alt???
That's very possible.
Yes, a bad diode in the alt can cause battery drain. The alternator gets switched on (electronically) when you turn the key on, otherwise the diode is supposed to prevent drain when the engine is off.
A corroded positive connection could cause a drain, with the corrosion products conducting a small current to ground.
I think I'd concentrate on connections and possibly the alternator before trying the battery drain test.
HMM -- Autozone says alt is bad, but dealer says it's OK? Given the dealer's track record and what you're experiencing, I'd be inclined to trust AZ, or at least confirm what they said with another test.
Ok. I will have another shop run a test on the alt. This weekend I hope to get to checking/cleaning connections. Gotta get this figured out before I am stranded this winter!
In 2002 the underhood fusebox was eliminated and they moved all fuses under the steering column. There is a post mounted on top of the drives side plastic fenderliner about the same place the old fuseboxes were that distributes power to the cab box. There is a hot wire coming from the battery that goes there then 2 fusible links from the inside fusebox goes ontop of that. It is in fact a hot post. I had a truck that would stall and act just like a bac cam sensor and it was that post corroded like yours.
Your plow has no ground and is searching for a ground through the frame. Check the plows ground wire and follow it all the way to wherever it grounds, usually the battery negative post. A good way to test the ground would be to plug the plow wires in but don't actually hitch the plow to the truck, the motor should be able to run with no frame contact, if not then the ground wire is disconnected or broken.
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2002 F350 CC SB Lariat 7.3 4x4 3.73 LS
Torredor Red, Viper 5701
Great info md18. What is the purpose of the post, and what are the side effects of removing the post and just bolting the wires together as the dealer did? I guess that at least removes my suspicion of the ground problem being related to that post being gone. I will check the plow grounds this weekend too, your method sounds like a great way to test for the plow ground. Thanks.
Great info md18. What is the purpose of the post, and what are the side effects of removing the post and just bolting the wires together as the dealer did?
I guess that at least removes my suspicion of the ground problem being related to that post being gone. I will check the plow grounds this weekend too, your method sounds like a great way to test for the plow ground.
Thanks.
There would be no side effect, that post is just a convienent place to join the wires together. Good luck on the ground wire though!
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2002 F350 CC SB Lariat 7.3 4x4 3.73 LS
Torredor Red, Viper 5701
Ok, I have some answers, but also more questions. I disconnected all of the wires from the batteries and cleaned the connections, including those for the plow. I then attached the positive cables and let the truck sit for 30 mins to "go to sleep". I checked the voltage between the posts, got a normal reading in the high 12s on both batteries. Then set the meter to 200ma, checked between the black cable and post, reading was 1 so I bumped it up to 2000ma and the reading was in the 600s, dropping at a steady rate. I disconnected the alternator and the rate of drop slowed noticably, but continued. I assume the alternator has a bad diode. Then started pulling fuses. No change in anything until I pulled the large ABS brake fuse. The drop almost completely stopped. So, bad alt and something wrong with the anti lock brakes??? I left the fuse out, the ABS light stays on but I can live with that if my batts hold a charge. I will replace the alternator. Hooked everything up and checked GPR while I was at it and that seemed fine. Then checked the plow ground as suggested by md18 and was thoroughly confused. I hooked up the plow wires without any other part of the plow touching the truck. The plow motor ran fine, so good ground, right??? I then hooked the plow to the truck, thinking I solved the problem by cleaning the terminals. Hit the button to lock the plow on and the sparks were still flying. Why???? Then, finally we held the meter on the battery while cranking to start. Passenger battery drops to about 10.6 cranking, which is normal. Driver side battery did not change at all, held 12.6 steady while cranking. Is that normal??? Sorry for the long post, really appreciate the help. Thanks.
Dan
But what is wrong? 3 cables come off the drives side postive terminal. 1 goes under the battery box along the side of the truck (to fuse panel ?), 1 goes to the plow solenoid, and 1 goes over the radiator to the passenger battery positive terminal. Passenger positive terminal has 1 line coming from driver battery, 1 line going to gpr, alt, etc, and 1 cable going to starter. How can I crank the truck and get draw of 10.6 on passenger battery but driver battery does not drop at all?????? Everything appears tight and both batteries are charging when running. I think I need to look at a wiring schematic...........havent even looked into the plow sparks yet.
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02 F-350 Reg Cab Auto Trans L2 Blue, Marinco Mod, ZooDad Mod, Bilstien HD Shocks, Ford Alarm Code 3 Remote Start, Energy Suspension Spring Bushings and SwayBar Bushings, 2500 Watt Inverter, Sirius Sat. Radio, (Hardwired), Garmin Nuvi 250 (Hardwired), Blue Sea 6 Circuit Fuse Panel X2, Western 8' Pro Plus Ultra Mount Plow, 08 Taillights, Stancor Mod, Ford AIC, AIH Delete, Stainless HPX, Foil Delete, 05 PTM Tow Mirrors, 05 Upfitter Switch, 05 Center Dash, Federal Signal Smart Siren with Signal Master...
I guess I should ohm test the cable going over the radiator. Maybe if the cable is corroded it cant draw large amounts of power from the battery but might allow small current from alt to batt to charge it? nycpsd, the plow is a 2003 BOSS 7 1/2 standard duty plow. The plow never had this problem until after I had the oil pan replaced. I have to assume that something didnt get re-connected correctly or something was pinched in the process when returning the motor to its original location. I see yours is a Western, any thoughts?
Since you stated that this problem only existed after motor was taken out ford tech might have reinstalled wires incorrectly or not at all for your plow the link below is the install manual so you can check. Also i would check to make sure the engine to frame ground strap was reinstalledstb03226.pdf
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02 F-350 Reg Cab Auto Trans L2 Blue, Marinco Mod, ZooDad Mod, Bilstien HD Shocks, Ford Alarm Code 3 Remote Start, Energy Suspension Spring Bushings and SwayBar Bushings, 2500 Watt Inverter, Sirius Sat. Radio, (Hardwired), Garmin Nuvi 250 (Hardwired), Blue Sea 6 Circuit Fuse Panel X2, Western 8' Pro Plus Ultra Mount Plow, 08 Taillights, Stancor Mod, Ford AIC, AIH Delete, Stainless HPX, Foil Delete, 05 PTM Tow Mirrors, 05 Upfitter Switch, 05 Center Dash, Federal Signal Smart Siren with Signal Master...
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??? I need some help here. Why are the batts slowly draining, and what would cause sparks between the plow and the frame?????? Thanks guys.
If the post and connections were corroded, then the wire beneath the insulation may have also turned into green goo.
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