2nd Gen Non-Engine/Transmission What's on when the key is off

[McLaughlin]

My daughter has a 96 CTD which wouldn't start this morning. She hadn't started it in two days and I'm curious to know what part/systems have power available when the ignition is off and the key is removed. I know the lights, door locks and cigar lighters all have power but is there something else?



When I checked the truck the batteries were both essentially dead (less then 8 volts) and both seemed to have the same amount of charge (i. e. neither one was totally dead as in shorted).



She's is sure her lights weren't left on and she had the batteries checked a couple of months ago but doesn't know how much water is in the batteries (I didn't check because a) it is cold out and b) it is dark out.



Once we got the truck started everything seemed OK voltage indicated a charge state, lights were as bright as normal, and after idling for a bit the voltage dropped some (to about 14 volts) to show the batteries were charging some.

 

[Philip]

PCM has power, radio/clock has power, brake lights, emg flashers.



I am not sure of what controls the grid heaters. But on a 1st gen the grid heater relays have power to them. I had one relay fail one time in the on position. 1st gen has two relays.



Also with the age of that truck the ing switch or its linkage could be leaving it partly in the on position.

 

[AMink]

The radio probably draws a little to keep the clock going. Was she able to cycle the preheater? If so, that might have been the last straw on already weak batteries. This morning I cycled the heaters once and turned the key... barely made a sound. I shut it off and let it sit for about 30 seconds and it fired right up. Read that on here somewhere . My batteries are probably 4 or 5 years old and don't hold a charge like they used to. This is the second time this has happened, both times I forgot to plug the truck in overnight. Might just be time for new batteries.

 

[McLaughlin]

The radio probably draws a little to keep the clock going. Was she able to cycle the preheater? If so, that might have been the last straw on already weak batteries. This morning I cycled the heaters once and turned the key... barely made a sound. I shut it off and let it sit for about 30 seconds and it fired right up. Read that on here somewhere . My batteries are probably 4 or 5 years old and don't hold a charge like they used to. This is the second time this has happened, both times I forgot to plug the truck in overnight. Might just be time for new batteries.

It cycled but acted REALLY strange. It was obvious nothing was working correctly when the heater grids were on. Even after we hooked it up to jump start, it took two or three minutes after the heater grids were off before we had enough voltage to start the truck.



She has no idea how old the batteries are (I'm pretty sure they are more than 5 years old). I suspect you are correct in that we need at least one new battery. Since she is on a budget, I may give her the batteries from my 97 (they work fine but are 3 or 4 years old). I was kinda wanting to get Optimas anyway and I can tell my wife that I'm making the sacrifice for my daughter .



Also, the truck has been somewhat of a problem for my daughter and she is thinking of selling it just to dump the frustration so putting new batteries probably wouldn't be real smart.

 

[AMink]

The batteries I have came from Wally Mart. They're the yellow ones. If she's going to sell it, I think I'd be chivalrous and give her yours and get the Optimas. What a guy! What other problems is she having with it?

 

[McLaughlin]

The batteries I have came from Wally Mart. They're the yellow ones. If she's going to sell it, I think I'd be chivalrous and give her yours and get the Optimas. What a guy! What other problems is she having with it?

A partial list:



ABS light comes on intermittently - goes out if wires under dash are moved.

Brake light comes on intermittently - goes out if wires under dash are moved.

4 wheel drive won't engage intermittently - goes out if connection on transfer case is move or on axle is moved.

Cruise doesn't work intermittently.

Heater/AC vents won't change from defrost intermittently.

Driver's side window won't go up and down intermittently - works correctly if wires by E-brake are moved.

Steering wanders/vague.

Low power - truck just doesn't accelerate like it should.

Transmission jumping in and out of OD - still under warrenty but the shop hasn't been able to fix after several attempts :{ .

 

[CTD12V]

McLaughlin,



Does the truck have power door locks? If so, did you happen to check the fuse for them? I pulled the power locks fuse on my '98 because I figured it was too easy to break in by shoving some stiff wire down through the weatherstripping to hit the unlock button. When I went to start up a few days later, the batteries were dead. I did this two different times before I realized that pulling the fuse was indeed the cause of my dead batteries. The second time was on my less-than-a-year-old Optima Red Tops. :{ But, on a side note, they proved to be worth the money. After trickle charging them back to full, they are still going strong a year later, and started my unplugged truck the other morning on the first crank at -18F OUCH! Anyways, for some reason I am at my wits end to understand, a missing fuse on the power door locks does drain the batteries. I would imagine a burned out fuse would do the same, so you might want to check that if it has power locks. Sorry for the long post.



Good Luck,



CTD12V

 

[CTD12V]

I just noticed your location is listed as Colorado Springs, too. You know the spell of cold weather I'm talking about

 

[AMink]

ABS light comes on intermittently - goes out if wires under dash are moved.

Brake light comes on intermittently - goes out if wires under dash are moved.

Might be the ABS sensor on the rear diff.

Cruise doesn't work intermittently.

Is this when it's cold? If you find the answer, let me know! Could be a corroded wire under the driver side battery tray.

Steering wanders/vague.

There are volumes about this on here! I think it was a standard feature. :-laf

Low power - truck just doesn't accelerate like it should

.

Is the fuel filter clean? Also, the overflow valve on the front of the fuel pump may be weak/need replacing. Easy to do. Do a search and you'll find how.



Don't know about the electrical gremlins, sounds like a loose ground or something. Good luck!

 

[nps]

Best way to check for batt drain is to unhook both batts and put an ammeter in series to see how much current is being drawn. Then pull fuses one at a time until the current draw stops. If it still discharges after all fuses are pulled, then probably the volt reg module in the alternator has a bad diode.

 

[McLaughlin]

McLaughlin,



Does the truck have power door locks? --- started my unplugged truck the other morning on the first crank at -18F OUCH! Anyways, for some reason I am at my wits end to understand, a missing fuse on the power door locks does drain the batteries. I would imagine a burned out fuse would do the same, so you might want to check that if it has power locks. Sorry for the long post.



Good Luck,



CTD12V

Yes it does have power locks(and a drivers power seat). Didn't check the fuse. I'd be confused also if my batteries died after pulling a fuse. I've pulled the power lock fuse on my 97 in the past when the passenger door decided to constantly unlock it self. Had the fuse out for about 60 days and never had a battery problem. For what it is worth, the truck complained a bit but started this morning.



Yeah, I know the day/night your talking about. If your truck started after a night at -18 you did a lot better then I would have. Mine was plugged in but had to sit out at work all day and the temp got all the way up to +2. I almost didn't get it started. Must have killed all the mosquitos though with the smoke because I haven't seen any since then(maybe the temps have cut down on them also though) . I''m thinking of getting the Optima yellow tops for the deep cycle capability; however, I'm not sure I want to loose about 50 to 100 CCA.

 

[McLaughlin]

Might be the ABS sensor on the rear diff.

I think there is actually a wiring harness problem under the dash. I just can't seem to get motivated to spend a couple of days pawing through the wires to check it out.

Is this when it's cold? If you find the answer, let me know! Could be a corroded wire under the driver side battery tray.

Doesn't seem temperature related. I may have found the problem for this. The vacuum hose connection to the fire wall seemed a bit loose. We haven't tried the cruise since I fixed that.

There are volumes about this on here! I think it was a standard feature. :-laf

Yah, I wrote part at least one of them volumes :-laf . My 97 is in pretty good shape now. I reduced the play in the steering from about 6 in to less then an inch(haven't aligned it yet). I've installed the 3rd gen track bar, the DSS, and the Luke's Links. All I have left to do is fix my ball joints and maybe replace the bushings in my front sway bar.



.

Is the fuel filter clean? Also, the overflow valve on the front of the fuel pump may be weak/need replacing. Easy to do. Do a search and you'll find how.

The fuel filter is less than a month old. Don't know about the overflow valve. I'll check that.

Don't know about the electrical gremlins, sounds like a loose ground or something. Good luck!

I've been told, been afraid to look, that the wiring under her dash is a mess. She had some body work done on the truck and the guys working on it accidently set off the car alarm. Instead of pulling the battery power they apparently just cut a bunch of wire and in the process fried the alarm system. Correcting that is stil on our to do list.

 

[McLaughlin]

Best way to check for batt drain is to unhook both batts and put an ammeter in series to see how much current is being drawn.

Thats about what I figured. Her truck started today so I left well enough alone. If it happens again, I'm going to hook up a ammeter and run the tests you suggested.