I am working on my 85 F250 4X4 351W 4 speed. I seem to have 2 problems but I'm not sure, I have VERY limited electrical knowledge. 1st problem is I have no emergency flashers, my turn signals work fine with no issues and my brake lights work fine. The fuse is good and I am getting power to the fuse, I replace the "flasher" on the back of the fuse box so that SHOULD be good but still no emergency flashers. How likely is it for the switch on the steering column to go bad? Any help/advice would be greatly appreciated.

2nd problem, my headlights have started pulsing, it's a very slight pulse but I can see it. The History: about 6 weeks ago, driving at night of course, my head lights (and tail lights} started randomly and rapidly blinking on and off. The way it acted was like a bad ground connection somewhere trying to "weld" itself back together. Pulled over to the side of the road and stopped and they continued to flicker/blink on and off for another minute to minute and a half. The head lights went completely out, I pushed in and pulled out the switch several time with no luck. I left the switch pulled out/on while I started calling a friend for a ride, all the sudden the head lights came back on and have "worked" ever since, other than the slight pulsing. Now for what I have done. As of today I have replaced the headlight switch, the dimmer switch, the alternator, and the voltage regulator. It's still daylight so I haven't checked to see if I fixed the problem with the pulsing. A friend of mine that works at the parts store said the pulsing sounds like the head light relay, I didn't know the head lights had a relay. He told me it keeps the power going to the head light constant, I have no idea. If there is a head light relay can anyone tell me where to find it and what it looks like? Either way, whether I've fixed the problem or not with the head lights I still have the issue with the emergency flashers. Any help/advice you gentlemen can give me is GREATLY appreciated, thank you in advance.

Oh yea, the battery is getting 13.8 volts at 650 rpms idle and about 14.4 volts at 1200 rpms, if that helps any. Thanks you.

 

It could be either 1 problem, or two,

Seriously... I have seen the wiring harness at the headlight switch connector melt and wires cross-connect when stuff heats up, behavior can seem really random when this happens.

The turn signal switches do wear out and pieces in that assembly break so there's that, too.

For the emergency flashers, you can measure for voltage not at the fuse but at the flasher's connections, one of those wires is hot all the time.

Look at Chapters 10 & 12 here:

1985 EVTM - Gary's Garagemahal (the Bullnose bible)

 

Headlights don't have fuses, there is a circuit breaker integral to the switch itself. 1985 was a long time ago, ground cables and wiring connectors get corroded and cause high resistance. Heat. That's what causes the lights to flash on an off. Did they still have a floor dimmer switch in 85? That's another area of high resistance.

 

Thank you gentlemen I really appreciate your input. That's a great link, I book marked it so I can use it. So I need to remove the new "flasher" I installed and check for voltage at the flasher connections? It's not a problem I just want to make sure I am understanding correctly. I was amazed at the size of hot wire that went to the flasher fuse, it was like an 8 gauge yellow wire.

So if I am understanding correctly Tedster9 since I replaced the headlight switch I also automatically replaced the circuit breaker for the headlights? Yes in 1985 the F250s still had a floor mount dimmer switch. I did clean the connector and installed a new dimmer switch.

Again I want to thank you gentlemen for taking the time to read my thread and help me.

 

He said what he is getting now is a slight pulsing. That is most likely the charging system at fault. Loose connection at the alternator, loose connection at the regulator, bad ground at the regulator, or the other day a guy had this problem on here and he ended up replacing the regulator and it fixed the slight pulsing he had.

 

Don't forget the factory splices between the alternator and the starter solenoid.

 

Unfortunately I don't have anything new to report today, a guy I know/knew came over today and WOULD NOT leave or get out of my way so I could get some work done GRRRRRR. He's one of those guys who knows everything and is a "Tommy Topper" on steroids if you know what I mean. Honestly I think he is "tilted", his cheese slid off his cracker. Sorry for the rant gentlemen I just hate wasting a day like this when I have so much to do, makes me so mad I could stand in the corner and rub &#!T in my hair.

I really appreciate all your input and suggestions/advice, thank you. Yesterday I installed a new alternator and voltage regulator so all those connections are good but I did notice there was not a ground wire on the alternator ground wire lug so I added one. I didn't even think about the factory ground wire splices so I'll have to check those tomorrow. I am also going to add some ground wires from the body and engine to the frame and ultimately to the battery. Again thank you gentlemen and please keep your thoughts and ideas coming.

 

Yeah, I know a guy like that but he is WAY worse than what you’ve described.

 

There should be a ground wire under one of the regulator bolts. If not, add one. It's important that the regulator is grounded. The alternator is grounded through the mounting brackets to the engine, but adding a ground like you did doesn't hurt.

 

Good morning gentlemen, LOL I know what you mean. This guy is a lot worse than I described to, I just didn't want my rant to go "to far". Thank God he's not around today LOL.

I added a ground wire from a regulator mounting screw/bolt back to the battery negative a while back so hopefully that is good. I am going to add some ground wires today from the core support to the fenders and from the fender to the wheel well and from the wheel well to the frame and the engine and see if that helps. Can't check the pulsing until it gets dark tonight. Hopefully the headlights won't be pulsing anymore.

Now for the flasher issue. With the truck shut off and the key in my pocket I removed the emergency flasher "flasher" from the fuse box and I have 12.3 volts going to one side of the flasher.
So IF my thinking is correct, please feel free to correct me if I am wrong, from the fuse box shouldn't the electricity go to the flasher switch on the steering column and from that switch to the turn signal wiring in the steering column? My turn signals all work so my thinking is since I installed a new "flasher" in the fuse box, for some reason, bad wire or connection, or bad emergency flasher switch the electricity isn't getting to the turn signal wiring in the steering column. Shouldn't I have electricity at the emergency flasher switch IF the wire from the fuse box is good?

I want to again thank you gentlemen for taking your time to help me with this issue.

 

So I guess it went right over your head, that my Tommy Topper was worse than yours? I shall claim that as a victory.

 

LOL Yea I got it LOL. I would love to take 2 of them and shackle them together and let them argue till they ended up in the nervous hospital LOL.

OK gentlemen, now for an update. I took the truck for a test drive in the dark and the headlights work perfectly with no pulsing what so ever. I am not sure exactly what fixed the problem but it is fixed so that's a win to me. One major head ache down one minor head ache to go. Any thoughts on the emergency flashers not working? In my humble opinion I THINK the problem is in the steering column but I honestly am not sure. I DO have power to the new flasher mechanism plugged into the fuse box So where should I check next? I wouldn't think the ignition switch (down low on the column) would affect the emergency flashers. My thinking is the emergency flasher part of the turn signal mechanism in the steering column is not doing it's job. Any thoughts would be greatly appreciated, thank you again.

 

Remove the steering wheel and test for power at the red/white-hash wire at the emergency flasher switch.




If you have power there and the switch isn't working, the problem is likely the switch.

If you don't have power there, check the 11-terminal connector between the TS switch and the vehicle harness, it's a sort of half-moon-shaped connector in the column down near the pedals.

 

These trucks use two separate flasher units, as confirmed by the diagram above. One for the turn signals and one for the hazards. Are you certain that you're working with the correct flasher?
Easy to test that theory if you have not already. While the flasher is removed try the turn-signals again. If they don't work, go on the hunt for the other separate flasher.

The hazard switch is "usually" part of the turn signal switch assembly too. That's for the older trucks and I'm assuming the same for the '85 is true?
Easy enough to take the wheel off for testing, but it might also be easy to test-probe the steering column connectors down under the dash. Hmm, guess that depends on your age and the condition of your spine! Now that I think about it, taking the steering wheel off sounds a whole LOT easier!

Good luck.

Paul