Probably and hopefully not to you guys though. BTW... I'm pretty new to forum but not to my beloved "Oscar", 90 F250 Stretch cab, Long bed with less than 74 K miles that I've had since 1989. BUT..... Oscar (and me too) has been having some difficulties since the woods rats did a number on the wiring a couple of years ago that required a wiring harness replacement, done at Ford dealership.

Since then have had a slow battery draining short that I've managed by starting and running or driving truck daily to keep batteries charged up. When temps get much below 70 F starting is difficult. Much below 60 F I need to use block heater. If I'm not driving daily I have to put the slow charger on batteries to keep them from draining almost completly.

I've had two different shops and three mechanics fail to find the short. Had to replace the batteries, a starter, an alternator, and many glow plugs and it is a real hassle to drag the charger in and out of the shed and carry that heavy charger and long extension cord around with me to friends' houses during moderately cool and cold weather.

After the engine warms up Oscar starts in a split second and runs as powerfully and smoothly as expected.

Last mechanic mentioned there was something "burnt up" behind and below the engine that "had something to do with the glow plugs" that he couldn't do at that shop so would need to take to dealership, which I don't want to do.

I know most of you guys here do most of your own work on your trucks. Although I have the aptitude to do so I don't have the time to learn, the facilities to do so, and probably not the strength to do a lot of the physical work needed for the mods (and improvements) I want to do immediately to Oscar to start using him for full time towing 5th wheel in not too distant future.

But first things first. I need to get this electrical issue taken care of once and for ALL!!!! Where do I take him? What do I tell them/him/her? Please contact me via email if needed. I'm in Dallas Co., south west of Dallas. For the upgrades, i.e. springs, wheels, brakes, tranny cooling (and maybe, but only maybe turbo charge), and of course a good paint job...... I would consider taking him out of state if needed.

Thanks, geekgranny

 

first things first, you need to figure out what circuit is drawing power. As far as upgrades, anything electrical? Audio, lighting, cb, flux capacitor?

One common place is the trailer wiring harness, as corossion and damage is more often found there.

What I would do is pull out all the fuses in the box. Then take a volt meter set to amp/DC or test light and go inbetween the two terminals. If you have power draw on that circuit, you'll get a faint light or amp reading. Some circuits you'll get that on, i.e. radio, ecm.

This exact thing happened to me on an '80 caddy. Turned out to be the + wire going to the starter. Had melted the insulation off where it was too close to the manifold. The bare copper had gotten corroded enough that there wasn't a full short, but drew enough amps to kill the batt.

 

with the info that something is burnt behind teh engine
park the truck and unplug the glow plug harness to the chassis harness teh plug is located by the a/c evaporator case it has two large yellow wires passing through it
if your batteries stay charged you have found the issue

 

Thanks guys. This will get me started this weekend. Now where did I put that voltmeter??