Hello,

I am new to this forum. I did a search of the forums but nothing exactly matched my situation. I have a 1995 F350 7.3l powerstroke. It is generally dependable but I have had electrical issues on and off. Over the years it has failed to start in the mornings several times. I search for a parasitic drain but cant locate it. I changed out the batteries. I took it in to ford but they claim it doesnt have a problem.

Then I finally realized that the battery always dies if the AC or fan switches are left on at night. This leads me to think there may be a short somewhere in that system causing this drain.

When the switch is turned off the battery drains slightly and has some trouble starting but usually starts on the first or second try. It does get harder as the truck sits for longer periods without a start.

I want to fix whatever short there might be because every so often Ill forget to shut these switches off and get stranded somewhere. Last time the batteries drained so much that a tow truck and two jumper batteries took about two hours to start it up.

Any comments or suggestions? Where might a short or drain occur in the AC or fan circuit?

Thanks.

 

First of all welcome to the forum. I was under the impression that the fan heater a/c system lost power when the key is off. Which brings up a possible stupid question, can you pull the key out at any point of the ignition position. Example, when I bought my truck the po never actually put the ignition to lock. He would turn it back till it stopped and would pull the key out. On mine there is a tab to allow the key to go to lock and accessories. My farm truck is the same way and an employee would keep turning the key all the way back to acc and removing the key ultimately killing the battery with the accessories. If that's not the issue then the next step would be to disconnect the positive leads on the battery, putting a test light from the positive battery post to the battery cable and removing fuses one by one to try to narrow down which circuit you will need to follow.

 

Thank you for the quick reply! Yes as a matter of fact my ignition switch has been messed up since I bought the truck. There is not a cover over the ignition key hole and I can remove the key in the ON position without any issue. I did not think this was a problem since I have known other ford trucks of similar age to allow the key to be removed when on.

I perform essentially the same procedure that you mentioned. I turn the key back until it stops (sometimes it is hard to tell) and remove the key. There is a small black plastic tab visible on the ignition switch. Perhaps this is the same as the one you mentioned, affecting power to the accessories? I will take and upload a picture in the morning so that you can see what I am dealing with.

How unfortunate if something so inexpensive as an ignition switch has been the culprit this entire time.

Again thank you for your reply!

 

Automatic or manual transmission?

Is the column locked when you remove the key?

 

This truck is automatic transmission. The column does not lock when I remove the key. I can drive it like that, just wont be able to turn the engine off without the key of course.

 

Here is the ignition switch in its present condition:

 

Okay so my problems may be solved.. I looked up some images of what the ignition switch is SUPPOSED to look like, and some face plates that show what the positions mean.

Strange that Ford sets the farthest back position to be accessories and lock, with a middle point between those and glow plugs being OFF. Weird. Anyway I expect that this issue will go away if I position the key properly.

Thank you for your replies.

 

That's not just a Ford thing. Well, at least it wasn't, way back when. The ACC-LOCK-OFF-RUN-START sequence, with LOCK being the only position where the key can be removed, was a "standard" used by American cars going back to the early '70s (or perhaps the late '60s), when steering locks were mandated to be part of the ignition lock. Imports started the LOCK-ACC-RUN-START "standard". GM must have picked up on that at some time; my Saturn follows the pattern started by the imports. The Saturn has an interesting mechanism; in order to have a position where the column is unlocked, but nothing key-dependent is energized, the column unlocks when you turn the key to ACC, but it STAYS unlocked when you turn it back to OFF. It only locks when you pull the key out.

Ford obviously hung onto the old pattern well into the '90s, perhaps later (someone with a newer Ford would have to clarify).

 

Did you ever fix the problem?
My 1996 f150 has the same issue

 

Run an amp draw test with a basic DVOM. Start pulling fuses until the drain is located. Once located, disconnect all accessories on that circuit until you find the culprit.

My guess is bad switch or hacker wiring.

 

My battery died a few times before and it had me stumped as to why
I had no idea what the lil lever was for until I replaced it.
This makes a lot of sense as why it has not happened since changing out my ign lock