problems with my 7.3L

[fordpower21]

Hello to all,
I have a 2001 f250 with a 7.3 diesel. My electrical problem started to happen two days ago. I was driving my truck from work and I noticed that my radio started to turn off and on. Then my gages started to move up and down. So I pulled off the freeway into a auto parts store. I took off the batteries and the alternator. I found out that one of my batteries were bad. In addition, my alternator also died. So I ended up buying a new alternator and one battery. This morning I hopped into my truck and it started right up, like a champ, but 20 minutes into my drive the same problems started to happen all over again. (Radio turning off and on and gages dropping). Is there anything else that I might be missing besides the alternator or batteries that have to do with electrical problems?

do both batteries need to be fully charged before i start my truck. or if i fully charged one battery, will the other become charged with the help of the alternator?
Thanks,
Fordpower21

[Wickky]

Sounds like you have some bad wiring somewhere and it keeps eating up your alternator... did you see that alternator gauge start getting lower and lower and lower as you were driving?

[NoRalPh]

Get another new battery, charge them both together.

If one battery was no good, the others not far behind.....

[dereku]

Yup you need to change them at the same time. Same if you have 2 alternators. Change them together.

[Black&Gold]

you should always put a new/freshly charged(good) battery in after installing an alternator, the initial strain on the alternator due to a bad/uncharged battery is horrible for it. i would buy a new battery for the one you didn't replace and check all fuses.

[03_Turbo7.3]

if the other battery checks out fine and you caught it in time i WOULD NOT replace it, i change one a year ago..and there both fine, both individually check out at 1000 cca a piece, and still no issues..i dont believe in the if one goes the other does, the only time ive seen it is when people dont catch it right away you get a bad cell in the sh!tty battery and it drains/ put harsh drain on the other battery..more load, remove all the wiring and test the battery, hell pop the caps off and make sure there full.

sound more like a wiring issue..

[Fast_Frank]

Check your grounds had same problem in my mustang the
wire was bad at the end near the block under the insalation

[bigcaveman]

When the gauges are working where is the battery gauge sitting at? I had a similar problem on mine and it ended up being a GPR was shorted and draining the batteries even when the alternator was good.

[fordpower21]

Originally Posted by bigcaveman

When the gauges are working where is the battery gauge sitting at? I had a similar problem on mine and it ended up being a GPR was shorted and draining the batteries even when the alternator was good.

When the gauges are working correctly, the battery gauge sit at a normal point. Then out of nowhere all the gauges start to flicker, and then the battery gauge just drops.

[bigcaveman]

Oh ok. Long story short on mine. batt gauge was in the norm for 15min while it was sitting. then I started driving and it drained the batt about a mile down the road. I made it to the parts store where I had the alternator tested and it was good. I had just changed both batteries the night prior for the problem and thought the old ones were just old. Well after my alternator cked good. I changed the gpr and havent had a problem since. Its been almost 2 and a half months. Dont know for sure that is your problem but might be something to consider. Easy fix before you dig into wires.