'76 pulsing headlights & swinging ammeter - pic

[GreensKeeper76]

I have a 76 FJ40 that I have replaced the alternator & battery &
voltage regulator. (I first tried a new rebuilt Toyota VR and then a
Transpo solid state unit - alternator is new Toyota OEM rebuild, battery is new Optima)

My headlights pulse, brighter & dimmer and my ammeter swings wildly at idle and less so at speed but the ammeter is never steady. Any ideas on how I might smooth out the electrical system to get stable lights and calm down the ammeter?

My only idea is that maybe the wires into the alternator are not set up right. (see pic of old alternator but wire set-up is the same on new one)

 

[FF LC FREAK]

First off, check your fuses. They tend to get a little corroded and not seat properly. I've had the exact problem you are describing and messing with the fuse and cleaning the fuse block cleared up the problem. If that doesn't help, start tracing wiring in the headlight circuit. Look for an exposed wire that is intermittantly grounding.

Good luck!

 

[GreensKeeper76]

Thanks for the ideas LC Freak. I will go check that stuff right now!

 

[Pin_Head]

What exactly do you mean by pulse?
How fast does it pulse and what is the relationship of pulsing with engine RPM?

If it is just random, maybe the brushes in the alternator are worn out. If it pulsates strictly when you rev it up, it is normal, since the alternator doesn't put out much power at idle.

 

[ducktapeguy]

I'm having the same problem, seems to have gotten worse since the radio installation but I could be imagining that. I'm pretty sure mine is the mechanical voltage regulator, I cleaned the contacts and it was better for a little while, but my headlights still pulse with the ammeter. I also have an optima red top, and I think the fluctuation was less noticable when I had a standard Diehard battery in it, not sure why.

Mine pulses kinda randomly, no real correlation to engine RPM or speed. Almost like someone playing with a dimmer switch, up and down, maybe less than a second between pulses, but not consistantly. I did check the voltage on my battery and it fluctuates between 13-15.5 V in time with the pulsing. If my battery is somewhat drained (like after leaving the headlights on without the engine running), it'll be fine while the battery charging. But as soon as it reaches full charge, the ammeter swings and the headlights fluctuate with it. I just assumed it was the on-off nature of a mechanical voltage regulator. I was hoping the solid state VR would fix it, but I guess it doesn't.

 

[GreensKeeper76]

What exactly do you mean by pulse?
How fast does it pulse and what is the relationship of pulsing with engine RPM?

If it is just random, maybe the brushes in the alternator are worn out. If it pulsates strictly when you rev it up, it is normal, since the alternator doesn't put out much power at idle.

Thanks for the replies. The alternator is brand-new Toyota OEM rebuild. The VR is a solid state transpo. Problem happens with new OEM Toyota VR and Transpo. The pulsing does not seem to vary much with RPM at all but is most noticeable at idle. I checked the fuses & block also. That seems good. by "pulsing," I mean that the headlights get brighter & dimmer, brighter & dimmer in a pulsing pattern. It seems to sometimes start after the engine has idled for about a minute.

 

[GreensKeeper76]

I'm having the same problem, seems to have gotten worse since the radio installation but I could be imagining that. I'm pretty sure mine is the mechanical voltage regulator, I cleaned the contacts and it was better for a little while, but my headlights still pulse with the ammeter. I also have an optima red top, and I think the fluctuation was less noticable when I had a standard Diehard battery in it, not sure why.

Mine pulses kinda randomly, no real correlation to engine RPM or speed. Almost like someone playing with a dimmer switch, up and down, maybe less than a second between pulses, but not consistantly. I did check the voltage on my battery and it fluctuates between 13-15.5 V in time with the pulsing. If my battery is somewhat drained (like after leaving the headlights on without the engine running), it'll be fine while the battery charging. But as soon as it reaches full charge, the ammeter swings and the headlights fluctuate with it. I just assumed it was the on-off nature of a mechanical voltage regulator. I was hoping the solid state VR would fix it, but I guess it doesn't.

Ducktape - My symptoms are exactly like yours. If the battery needs a bit of charge, there is no problem. Can anyone confirm that my alternator wiring in the pic above looks correct?

 

[nuclearlemon]

white with blue stripe is correct.

guesssing that the brown goes to a white with black stripe, then it is correct and the other wire should go to white with green stripe. your voltage regulator should be set up for a three wire plug, not a six wire plug.

 

[GreensKeeper76]

white with blue stripe is correct.

guesssing that the brown goes to a white with black stripe, then it is correct and the other wire should go to white with green stripe. your voltage regulator should be set up for a three wire plug, not a six wire plug.

I'll have to open up the harness to see what's been done in there. The transpo VR does look to be set up for 3 wires and it's had a relay wired into the circuit as well. I'll get a photo of the diagram the electrical shop did for me about 8 years ago! Thanks for the reply!!

 

[Pin_Head]

Do the lights still flicker with the alternator disconnected? That would pretty much rule out the alternator and VR if they do.

 

[GreensKeeper76]

Zippy -

Do you mean to start the FJ with all the wires out of the alternator? Can this be done safely?

With the car not running, the lights do not flicker.

 

[Pin_Head]

Zippy -

Do you mean to start the FJ with all the wires out of the alternator? Can this be done safely?

With the car not running, the lights do not flicker.

Yes and yes. This would pretty much rule out what the alternator does for this problem. Does it still flicker driving around with the alternator disconnected?

 

[GreensKeeper76]

I will try this first thing in the AM!!!

 

[Pin_Head]

Why not do it when it is dark and you can see the lights pulsating?

 

[GreensKeeper76]

With the alternator disconnected the headlights do not pulse but the alternator is a brand new Toyota rebuild and the lights pulsed with the previous alternator as well.

Maybe a bad ground?

 

[ducktapeguy]

I just replaced my VR with a new SS one, it seems to have cured the problem. My ammeter is rock solid now, no more pulsing of the headlamps or interior lamps. I took apart the old VR, it looks like one of the contacts were burnt and eroded. I had replaced this one about 3 years ago, but I guess they don't last? Anyway, I don't know if this helps you, but that's what I found.

Also, I repaired the old OEM mechanical VR and tried plugging it in, and the ammeter is also stable. So it didn't make a difference in performance for me whether it's solid state or mechaincal, but whether it's working properly or not

 

[GreensKeeper76]

I have a Transpo VR in there that I guess I'll be replacing next. Thanks for the replies. Much appreciated.

 

[Pin_Head]

If the lights flicker when you hit a bump, it may be a lose connection. It could also be a bad ground between the alternator and regulator. This is so important that Toyota actually used a wire between the two instead of using the sheet metal mounting surface. Is this white/black stripe wire in place?

It is probably not a bad regulator as solid state VRs don't fail like that. While the flicker might be annoying it is not a critical problem.

 

[GreensKeeper76]

There does not appear to be a ground wire coming of the VR. How would I wire this ground up?

I ordered a new Transpo IN554 VR anyway and we'll see what that does also.

 

[GreensKeeper76]

Here are two photos:

1) The Transpo IN554 area, showing how it was wired up with a relay, etc.

2) The wiring diagram done when the Transpo VR was put in.

Any expert opinions on this set-up?

(It looks like a ground is coming off of "85" on the relay)