OK, everyone has been so helpful here and provided me answers to all my questions, so here is a new one.

I'm having issues with the dash lights in my 1965 F-100 Pick-up

1st - the high beam indicator bulb illuminates when the dash lights come on, but will illiumunate brighter when I turn on the high beam lights.
2nd - all of the dash lights illuminate dimly.
3rd - the Alternator light glows dimly all the time but the alternator checks out as charging.

I replaced all of the dash lights and cleaned all of the light sockets and the issues remain.

Could these issues be caused by a bad instrument panel voltage supply?

Thanks in advance for your help!!! John

 

It sounds to me that the metal part of the instrument cluster isn't grounded properly. You can check by touching a grounded wire to the back of the cluster and see if all or any of these problems go away. This may not explain the ALT light being on, though. It is grounded through a contact in the voltage regulator.

I'd have to look at mine to see if grounding is normally done through a wire or one of the mounting screws.

The instrument panel supply only provides power to the gauges. The different lights get their power from different sources. (I.E. the ALT light from the ignition switch, illumination form the headlight switch via a fuse, high beam ind. is from the high beam filament circuit from the dimmer switch)

Hope this helps,
James

 

I'm wondering if you have three different issues. I agree with JMEvans that you should look at your grounds. First of all, you do know that your instrument panel lights are on a rheostat that is part of your light switch? This may sound like a stupid question, but some people have overlooked this fact. When I redid my instrument panel and had it all apart, I labeled each wire as to where it went and then checked each of them for proper operation without the I/P being installed. So the high beam indicator light only came on when the floor dimmer switch was pressed. And the alternator warning light only came on when the ignition was turned on with the engine not running. The reason I bring this up is I wonder if you are getting light bulb bleed over into the high beam and alt warning locations from your instrument panel lights? So it would be worth checking when those bulbs really come on without the panel and other lights in the way. It's a bit of a pain to do, but at least you'll know what's really going on. Good luck!

 

Turning light switch **** to the right dims the instrument cluster lamps. Turning it to the left turns on dome lamp.

Amp warning (idiot) light tends to glow or flicker at idle: Check the alternator belt tension, something many people overlook.

 

Thanks for all the info!

I did label each wire when I removed them and the high beam indicator does illuminate when the dash lights are engaged.

I also checked the rheostat settings on the light switch which I also replaced due to a headlight flashing indication.

I have not attempted to ground the panel seperatly but I'll give that a try and let you all know what occurs.

 

So you have already replaced the light switch? Without trying to insult you, did you get a good one? Ford service parts switches are readily available. So, too, unfortunately, are poorer quality ones. I seem to remember some posts a few years back complaining about the results of installing substandard switches. My '66 model wiring diagram shows four wires attached to the headlight dimmer switch: There's a red with black trace that comes from both headlights through the firewall main disconnect to the dimmer; two green with black trace wires - one that comes from both headlights through the firewall main disconnect, and the other comes out of the dimmer switch (from the same post) and dead ends at the high beam indicator light. The fourth wire is red with a yellow trace and goes from the dimmer switch to the plug on top of the headlight switch. I'm just wondering if your stray voltage that is causing the indicator to light when it shouldn't is located somewhere in that last wire/plug/new switch? Of course I could be (and frequently am) wrong, but it's one place to look. Good luck!

 

It's the ground. Sweep speedo's have a black wire from the back of the cluster over to the pedal support. This wire is to short and always gets broken. Replace it with a longer wire and solve most of these problems. I also like to use bulb grease on all the bulbs so they come out next time. JMHO.

 

Just sayin I 'm having same problems , battery shows 14volts when running. alternator light burns