Weird truck electrical issue

I own 3 pickups. Last week I hit the trifecta with one truck down with a bad transmission, the second truck down with the slave cylinder on the clutch failing, and the third refused to start.

The first two were easy diagnosis and the repairs straight forward, new transmission and the other replaced the clutch setup from the pedal to the flywheel. The third one has everyone stumped.

An old 1984 F150 with a 351W and C6 transmission. Pretty straight forward. Except - last fall the truck would act like the battery was dead - sometimes immediately after it had been shut off and other times it would go days without an issue. When it acted like the battery was dead you could jump start it and or put a charger on it overnight and the next morning it would fire up no issue. It might run fine for a week or you could drive it around the block shut it off and act like the battery was dead again. Replaced the battery and my son thought the voltage regulator was dead. He replaced it and the issue continued. Then the day came when none of the lights would work either. I finally brought it to a shop and they diagnosed the voltage regulator not being properly grounded as the issue - and the ungrounded regulator had fried all the light bulbs. They checked the alternator after bolting down the regulator and said everything appeared to be charging and working as it should. They simply bolted the voltage regulator tightly to the fender and replaced all the bulbs (I hated hearing I had paid someone to change light bulbs). I though OK, the old regulator was bad, and because it wasn't grounded the new one didn't work correctly.

The truck was driven very little the couple months as no one trusted it to go anywhere. When the other two pickups went down the 84 was needed. First couple of days it ran fine - then it was finally driven at night - next morning it was back to the battery acting completely dead. First time you turn the key you get a click from the solenoid then nothing after that. Left one son stranded in the morning when he got up to go to work - apparently he got mad and twisted the key extra hard and broke the actuator.

Couple days later I replaced the actuator installed another battery from a tractor and it fired right up. Drove it across town with the lights on (about 10 blocks or 5 minutes of driving). The amp meter stayed dead center (working?) did not indicate decharge. Shut it off to fill with gas so I could get home. Jumped in and the solenoid clicked once and then nothing. Had my son run by and tried to jump start it - his little battery and light duty cables only got the solenoid to grind but not engage the starter. Pushed the truck to parking stall and cursed it for a while then took my ride home. Last night I tried to jump start it with my car (1000 cold cranking amps, new battery and heavy duty jumper cables) the solenoid would only grind. Left the jumper cables on with the car charging the battery for about 20 minutes then it did just barely start - drove it home and put a trickle charger on it. While my car was charging the pickup battery I didn't get any messages from the car's computer system warning decharging battery or other diagnostic issues.

What would cause this? I would have said a grounding issue but the battery appears to be actually dead - even after just a few minutes of use. It does it on multiple batteries (3 or 4 so far) otherwise I would have thought a battery with a short. It seems to happen more often after using the lights but I can't see the lights draining a battery in a few minutes just going across town (small town). The headlights are new and appear normal when used - not extra bright or dim (part of the many bulbs replaced by the shop) or I'd think electrical short - and any electrical short that could drain a battery that fast I would think would also cause a fire. The few times it has had voltage checked with a multimeter is shows charging at 14+ volts.

Today its getting a new good voltage regulator (son admitted he bought the absolute cheapest one he could find) - and new heavy duty battery cables - ground and positive.

Similar issues with a '76 F100, turned out to be a badly corroded positive battery cable, but the cable looked good. Absolutely NO outward signs of a problem. The corrosion was all inside of the plastic sheath.

1980 Ford Fiesta. Battery would run down while driving, but not while just parked. Traced that problem to a defective, electronic turn signal flasher unit. Replaced it with a conventional style flasher unit and problem solved.

The cables look poor - primarily replacing them to eliminate one possible issue (still might be a combination of issues). But even with a bad cable I'm surprised the battery appears to be dead.

As mentioned by Rusty, I am thinking its a poor connection somewhere in the system. We had a Ford 4000 that did exactly what your truck is doing. Ended up being just the chassis end of the negative battery cable. Have you tried wiggling wires around when you get the symptom? That might help identify where the issue is.

Black corrosion on a battery post can cause similar problems and may take a knife get off.

How long has the truck been setting? How old are the battery cables? First, when a battery just clicks on the starter motor relay (solenoid) it usually means a dead battery. When you jump start a vehicle the dead unit start because you are using the host vehicle to supply power to the dead vehicle, then the next day battery is dead again and won't start. Next, you need to get into the entire wiring system thoroughly to get to the true root cause and stop guessing. A weak or dead battery can be tested quick and easy, usually at no charge (pun intended) at your trusty local starter/alt shop on their special test equipment. Simply connecting your basic garage trickle charger won't do it. After a week or so a normal battery will start to deplete specific gravity, lead plates get weak, and if charger left ON could overcharge and boil out the water and electrolyte. You cant just add more electrolyte and water - it doesn't work that way. A good starter shop may be able to troubleshoot your electrical system for you. Wiring, battery cables, VR, shorts in lights - any one or a combo of all can result in the problems you are having. If vehicle will be idle for a week or longer, invest in a FLOAT CHARGER such as the DELTRAN BATTERY TENDER, about $30 at Wally World. A Float Charger maintains a full charge so it is ready to go when you are. It will shut off automatically to prevent overcharging and kick in when it gets low to deem a charge. Once you get system all right again, invest in one. I keep one on all my tractors. My cars and trucks don't set idle for days.


DELTRAN BATTERY TENDER - A VERY GOOD FLOAT CHARGER:
*Note: The JR unit is the 6V model.

Tim Daley(MI)

It's not uncommon for there to be a bad internal connection between the lead battery cable end and the wires inside it, especially when more than one wire enters the lead end.

When it appears to be ''dead'' check directly between the battery POSTS with a test light.

If that shows the battery has power, turn the headlights on for a load, then use the test light between the (-) battery POST and the chassis. If the light comes on the poor connection is at the ground side.

Do the same thing between the (+) POST and the battery-side terminal on the starter solenoid, and wherever any additional wires from the (+) terminal go. With the headlights on and potentially drawing power the test light will come on when across a bad connection.

I am betting you will find the problem inside one of the cable ends.

If NOT, there's several fuseable links feeding various circuits from the solenoid stud where the battery cable attaches and weird things can go on with the fuseable links or the connections at either end of them.

I had a similar problem with one of my old tractors, it would start OK most of the time then suddenly no start, starter did not turn over and the solenoid got hot. Would work fine for months, then when you were in a hurry it would not start. Found it was a faulty starter in the end, replaced the field coils and now it is fine.

I had some funny electrical issues with my truck. Mechanic knew right where to look for a bad ground, his wife had a similar vehicle and it left her stranded. He had her truck flatbed to his shop where it started right up, took him a while to figure it out.

I had a drain on my 79, ford years ago. Came out from work and dead dead battery. Jumped it and got it home. Put and amp meter on the positive side of the battery. It showed a 4 amp drain with everything off. I started un pluging everything 1 at a time and pulling fuses. I even unhooked the alternator. It turned out being the electronic voltage regulator on the fender.

Gremlins spread when wires are old and get wet.

Sounds to me like your battery cables are probably bad or ground somewhere.

IF the cable chasing, wiring, or the battery all end up checking out I would look at the ignition switch, Duralast Ignition Switch LS503 as an example. I had a 1985 F250 4x4 manual trany w/351 back in the late eighties/early nineties. At random times I would try to start it and get -nothing- so I replaced the ignition switch that is bolted to the lower steering column with a wire bundle attached to it. No more problems. This truck had been rode hard and put up wet with no telling how many start cycles on it. Basically on my truck, and I'm thinking yours too, the key turning moves a metal rod down the column to this switch which then gets the electricals to work(in theory). It was a bear to get to but solved my issue. I hope you get yours going.

Run a wire from the Neg battery post to the base of the solenoid , to make sure it has a good ground.

If you invest in a good volt meter it can tell you a lot.

Sounds like a bad connection, ground, cable or a combination of the 3.

Forgot to add, the ECM gets its power from the POS post, if that wire is shorting or going bad you will get all kinds of electrical issues. BTDT.

Sorry if I missed it in you story but the one thing I cannot tell is what your definition of ..acted like the battery was dead means.. When that happens if they are working do the interior lights come on when you open the door? When you turn the key do the lights come on in the instrument panel? If you did have some indication of power and then it did not start you need to look at the solenoid and starter, not sure if that era Ford still had a solenoid on the inner fender. Also not sure where the voltage regulator mounts but I would probably suggest adding a separate new 12 gauge ground to one of its bolts and over to where ever the negative ground battery cable is connected to the chassis. If it continues to do this when it does not start you need to turn on the head lights and see if they shine when it does not start or if they go real dim or completely out. Maybe keep a large piece of cardboard box with you to lean up in front of the truck for the lights to shine on when this is a problem.

Most of the interior lights don't work on this truck (no radio either). But yes - the head lights will sometimes come on very dim - other times nothing. Not enough power to make the solenoid do more than click - and sometime not even that. I would immediately say battery cable but if you put a charger on it overnight it will fire right up in the morning. Or as when I was trying to jump start it when I let my car charge the battery for 20 minutes it finally had enough power (with the jumper cables still attached) to engage the starter and very slowly turn the engine over just enough to start it.

I learned all about the metal rod that engages the ignition switch - watch the process to replace the ignition actuator. I can't believe that Ford using that system right up through the 1990s.

Have you put a load tester on the battery when it "acts dead?"

Actually check to see what the condition of the battery is before assuming it's dead.

I had VERY similar behavior from my 2015 Chevy over the past couple of years. You'd jump in turn the key and *click*. I'd jump it and it would start and be fine for a while. The battery didn't test bad with my carbon pile tester, but I replaced it anyway. It would be fine for weeks or months, then all of a sudden *click*. Come back 10 minutes later and it would start fine.

It ended up being the starter itself. Replaced the starter, and knock on wood, so far so good.