Hello, 1996 F350 PSD, automatic. Just under 300,000 miles. Batteries drain in a matter of 2-3 days. I have disconnected the batteries, reconnected three days later, and plenty of power. I know the Glow Plugs aren't working, but $$$ and time has delayed that fix. I plug in when I know I am going to need it. In trying to chase this problem down, I know I can start pulling fuses. I have to get a fuse for my meter tomorrow, or pickup a test lamp. I read in another post about a starter relay on the right side on firewall? With three fuseable links? I cannot locate this. Of course it is dark out, and flashlight is not the best... Does this exist in 96? If so, can someone give me a explanation on what to look for? This seems like a good place to start. Glowplug relay is possible, I may just disconnect the relay to see. The alternator has not ever been changed by me, so 9 years and 100,000 miles at least. Any other ideas?

Thank you

Andrew

 

You need a meter to start checking for any voltage pul on all the fuses with the key off. If its killing the batteries in two days you should find a circuit with a pretty good pull.

After the truck has cooled down go touch the alternator and see if its warm

 

The old parasitic voltage leak....BTW, that fuseable link is wrapped up tight on the wire going from the alternator to battery and that I'm sure is not it. X2 that on using a meter to methodically check each fuse connection to ground for low voltage..First the engine fuse box and then the cab and look for any homemade connections with stray strands.

Since you;ll be doing all that, you might as well document for all of us which are switched and unswitched.... zzt zzt !!

 

The fuse had blown on my meter to measure the current flow, so my wife going to town for other errands picked up new fuses. In the meantime I made connections to batteries, and measured voltage at the Glow Plug Relay. Hot on one side only, turned key on, hot on both sides, measuring right about 12 Volts. I then disconnected the batteries. Wife returns, put fuse in meter, make connection with meter to measure current, and POP, blow another fuse in the meter..... What did I do wrong? Hint, read carefully above.... I never shut the damn key off. Anything greater than 10 A will blow fuse. Next trip to town, we will get another fuse. So now trying the unscientific way... Pull fuse, touch cable to battery. Did this for every fuse in both under the hood, and in the CAB. Always got a significant arc.... About the same every time (with the key off). Disconnected both wires from Alternator. No change... Checked battery cable between the two batteries, and down as far as I can see, saw no signs of problems. Crawled underneath, some corrosion but nothing looking like a problem, but can't be sure... A second cable attaches at the right hand battery, runs across above the engine, in front of the firewall, to the drivers side, and down, looks like it goes into the cab I think. Disconnected that, no change..... Is there a way to disconnect power from the distribution box under the hood, and from the fuse box inside the CAB? Either way, I am done until I get a new fuse in my meter.....

 

It sounds as if you're taknig the batteries full amperage. Test your meter first to see if it hasnt blown a resistor...Put ot high resistance and touch both leads together..you should get continuityand then check for 12o volts in a known good receptacle to make sure that works and then test a cheapo battery (AA,AAA,9v). If it checks out fine sonnect the black meter probe to a good ground and leave it connected there as you probe with the red on the connections points looking for positive voltage. BTW, with the black lead connected, test it for continuity as well to ensure it is indeed good.

 

You could always wrap the fuse in foil to get you by. Just make sure you have your netter set correctly

 

That;ll work, drats,,,that reminded me to pull the dime out of the box I shoved in last year...

 

Did you disconnect the big charging wire on the alternator when checking?

 

Yes, Big Charging wire, and the two plugs....

 

Thanks for the reminder on how to "mend" a blown fuse... So, I started checking. I was showing a .39 draw on the battery. Went through the entire Distribution box (under the hood). Two fuses involved. Fuse 1 (small 20 amp fuse) when pulled takes the draw down to .28. Fuse 20 (large 50 amp fuse) takes the draw down to .14. Pull them both, and the draw shows .03. I came in and started writing this up, but then decided I wanted to check out Fuse 20 further since it appears that it feed four fuses inside the cab. I first went to double check my results on the distribution box. I only now recorded a draw of .14. Fuse 20 now had no effect. This is not nice, as sounds like something that will come and go. Fuse 1 still does affect the power draw.. According to what I can tell, it indicates the audio power. I do have a different radio in, my son put in the truck last year... I don't even know how to pull it out... In addition, the cable from the right battery I mentioned that goes into the cab. I think this is feeding a power amplifier sitting behind the back seat. I just disconnected that cable. So now, looking for ideas... Both Fuse 1, how to trace, and has anyone else experienced this. Fuse 20, same thing.

Oh, and one more thing. Once I connected everything back up and started the truck, the battery light stayed on. The gauge indicated charging, right in the middle. My damn meter (problem with connection on it) doesn't want to record anything. Has anyone seen where the battery light stays on, but charging ok. It did eventually go off, but just making me think a little here. Thanks for your help. I know, I need a new meter, but this one is about damn brand new......

Andrew

 

Check your glove compartment lamp. It is on the fuse #20 circuit and is known to stay on when the door is closed. Might have to sneek up on it at night or just remove the lamp and re-test.

 

^^^DO THIS FIRST^^^

Few things. foil on a fuse is a bad idea. could ruin the meter or the circuit being tested. next, the probes of the meter plugged into the fuse socket will also be able to measure amps on that circuit. third, the power wire to the amp should be protected by a fuse at the source (at the battery). people dont think it could happen but you COULD have a fire from something like that. and finally a road map of the circuits youre testing is a huge help. it helped me diagnose a charging problem on my nephews f150. so here are some wiring diagrams for the truck. they show fuse size and number. they may or may not help if you dont know how to read them. they do show wire color. yours is a year older than the diagrams but ive heard that theyre mostly the same so your milage may vary. worth a try.

 

For the battery light, check the small single wire connection on the alternator.

 

Thank you everyone. The Power wire to the amp is something I inherited when I bought the truck 9 years ago. I did not know that is where it went. Not 100% sure now, but 99%. It is now disconnected. Don't care at all. As long as the radio plays, that is all I care about. I will look at the wiring diagrahms, and then possibly pull the radio to check for anything there... Glove light checked, not staying on but will watch it, but don't know that it would cause that much draw.

 

If you get to where fuse 20 is drawing, unplug each of the 4 fuses it feeds in the cab one at a time and recheck 20 to narrow it down