Electrical Draw hell

[trouble]

Help! i am out of answers. 1990 f250 7.3 with a draw that will drain the batteries ovenright. (i hook to battery charger every night) 2 years fighting this and 2 shops. so last week im workin onit again. disconnected power lead to starter solenoid on in fender wall. short gone! so i replace the solenoid. draw still there. so i check the 5 wire leads at the +post. one, when disconnected,
stops the draw. it powers the pcm. so yesterday, a new pcm. (mall of ga ford- $275) put it in, drain still lives! i disconnect pcm lead at starter solenoid, drain still lives! check the other wires (which showed no problem prior) and another shows up- when disconnected, drain disappears- this powers the dome light and ignition circuit. ford guy suggests looking at glo plug relay- so i take the cover off (crack one of the 'snap fingers' in the process) , disconnect the power lead on top, AND THE DRAW REMAINS. not knowing what else to do, i go back to the starter (already checkeda0, disconnect it, and the draw remains. I quit for today- will go back to the charger/disconnect the leads at the starter solenoid at night.....

 

[typ4]

check the alternator power lead and regulator. Pull fuses also to eliminate those possibilities.

 

[bigdadydiesel]

Try the ignition i have heard of them giving problems.

 

[tknomaj]

Isolate which fuseable link has draw then run dow diagram and unplug until draw goes away . remove pos battery cable and push to side connect aligator clip of test light to battery cable and use rubberband /zip tie or vise grips to hold test light to battery when you unplug item causing draw light will go out as you go down harness do not forget to wiggle and flex it this will let you know if draw is in harness not the best way to check but fast and easy and not allot of out of pocket expense for tools

if the draw is in the transmission control module check relay that powers it it may be the problem

 

[MIDNIGHT RIDER]

Check the alternator.


An alternator can develop an internal short and drive you crazy, until one night it burns the barn down.

 

[sassyrel]

Check the alternator.


An alternator can develop an internal short and drive you crazy, until one night it burns the barn down.

this internal short---is in the diode plate-----they can go bad three ways. they can let the current reverse when truck shut off, flat burn out, or short to ground. sooo, you can have it checked--and it may check ok if the diode is reversing, but will drain the batts overnight--

 

[sassyrel]

trouble--disconnect the hot wire on the alt overnight. if batts up in morning--diode plate inside alt has went south. get a local alt shop to replace the diode plate, and check the rest out---the reason being is that are soooo many horror stories of rebuild alts---------------

 

[trouble]

thanks

trouble--disconnect the hot wire on the alt overnight. if batts up in morning--diode plate inside alt has went south. get a local alt shop to replace the diode plate, and check the rest out---the reason being is that are soooo many horror stories of rebuild alts---------------

is alt rebuild cheaper than buying new?
is there an 'ignition module?"
thanks

 

[trouble]

thanks

check the alternator power lead and regulator. Pull fuses also to eliminate those possibilities.

pulled fuses first.
checked alt by disconnecting power lead and running test light btw neg battery post and neg cable. light still on.

what regulator?

thanks

 

[trouble]

thanks

Try the ignition i have heard of them giving problems.

is there an 'ignition module?'
thanks again

 

[trouble]

thanks

Isolate which fuseable link has draw then run dow diagram and unplug until draw goes away . remove pos battery cable and push to side connect aligator clip of test light to battery cable and use rubberband /zip tie or vise grips to hold test light to battery when you unplug item causing draw light will go out as you go down harness do not forget to wiggle and flex it this will let you know if draw is in harness not the best way to check but fast and easy and not allot of out of pocket expense for tools

if the draw is in the transmission control module check relay that powers it it may be the problem

first thing i did when my test light went out was replace the starter solenoid, which powers the pcm. didn't work.
will get to work on the harnesses...
what do you think of alternator? when i disconnected power lead, test light from neg batt post and neg batt cable still lit....
thanks

 

[tknomaj]

Your truck has no pcm and has up to seven fuseable links that attach to starter soleniod have light connected and remove bolt at soleniod and remove fuseable links one at a time then you have jus isolated (found ) the circuit with the problem check wire color and print the first diagram and follow that circuit unplug or disconnect items shown on circuit one at a time until light goes out the problem is either a bad relay/ alternator switch but when removed light will go out if it does not then move flex wiggle wiring loom (two people one watching light and you wiggling flexing loom until the light flickers or goes out that will tell you where to open loom and look for damage (short to ground)
snap-on makes a tester that is fast and easy to use by your self but costs about 250.00 and is not worth money unless you do this all day most mechanics cannot find shorts due to it takes time and the understanding of electrical and most don't that is why people have such bad things to say about electrical/short repairs

 

[tknomaj]

you are working on the truck in sig right?

 

[tknomaj]

pulled fuses first.
checked alt by disconnecting power lead and running test light btw neg battery post and neg cable. light still on.

what regulator?

thanks

the voltage regulator is built into your alt or could be seperate pulling fuses will not tell you any thing if short is in front of or not on fused circuit from fuse panel that is why i told you to start at fuseable links to locate circuit it is in once we know what circuit we can run down circuit and locate and repair

 

[MIDNIGHT RIDER]

most mechanics cannot find shorts due to it takes time and the understanding of electrical and most don't that is why people have such bad things to say about electrical/short repairs

It is rare indeed to find a greasy wrench-turning mechanic that can wire worth a durn.

I think some of this is due to customers having absolutely no idea just how much TIME is involved in doing something that to the ignorant looks simple.

It takes patience and lots of time to properly splice/solder/heat-shrink every single electrical connection.

Customers are not willing to pay for this time, hence the down and dirty, twist the wires together and big wads of black tape, or worse yet those so-called "quick-splices", "suitcase connectors", "scotch-loks", or whatever.

If a vehicle starts and can pull itself down the road, most consider it "fixed".