Light shorting help? With pics. Please Advise~

[04stangman]

Sup guys, I have 69 F250, 390 auto, as you all probably know by now. The last few times I drove my truck I could here a little popping or clicking sound. My dash lights shut off and so did my rear lights, then they would start to flash off and on. So I took some pics of what I think is a relay, its the thing that was making the noise. It is located on the passenger side of the cab wall under the glove box. Here is the pics.










So, I See see a cluster of wires and plugs, red, yellow and black, I have no idea what they are, where they go or what they do. Then there is the relay, I think that is what is is. I went to napa and replaced it, they told me it is a 12 volt relay. So, I got a new one, came home and hooked up.

The good news is the new part, (relay)? is not making that intermittent clicking sound anymore. but the bad news is my dash and rear and lights are still flashing on and off, just the dash and the rear lights. So I try to investigate some more and it sounds like the main light switch is making a clicking sound right behind the dash?

So, After I get done being mad I tried to get the switch disconnected and I cant figure it out, how to get it unplugged and disconnected. But, while in the process I felt what I think is a little button on the top of the switch assembly, located on the top part of the plug or housing assembly underneath and behind the dash. I pressed it a few times, tried the lights again and for the short drive I went on the lights worked, nop problems!

So, my questions are,

What is the part in the pic and what does it do, I think its a relay.

And, is there some sort or reset button on the top rear side of the light switch assembly? Like a reset switch?

The 3 colored plugs next to the (relay) what are they and where do they go, Red, yellow and black.

And, is there anything that you guys think I need to check?

Thanks for the help, it seems s like I have one thing happen after another! But I love this old girl, and with all of you r help, see can keep running.

[lobuck76]

The little button is for releasing the knob and stem from the headlight switch.
I'm no wiring expert , but the clicking on and off usually means a bad connection or short (getting hot). Or bad ground. I would feel around for hot wires.

[AlleyCat]

The part in the pic is a relay.I'm not sure what it's for.

The button on the light switch is the release for the knob. Push the button in then pull the knob out. It will go past it's last stop and pull out of the switch. Be sure to disconnect the battery first as the lights will be on.

Ford trucks are notorious for light switch problems. When the lights start flashing off and on it's the truck's way of telling you to replace the headlight switch. Add age, corrosion and sometimes owner installed lights to rather poorly designed system and the switch starts to burn out from overheating.

[04stangman]

Hum, so if I replace the the headlight switch switch, how hard is that? Does anyone have any instructions. I cant figure it out? Also, does anyone know if this is the right one? Thanks.

http://www.autozone.com/R,1281649/vehic ... Detail.htm

[Thunderfoot]

The relay on the passenger side is for marker / cab lights... I don't see any on your truck so not sure why you have it, unless it has a different bed or something on it.... The thing that was bolted to the left screw of it is the circuit breaker for the power to it. See this diagram for how it is hooked up normaly... http://www.fordification.com/images/sch ... arkers.jpg

The Red, Yellow, and Black connectors are for the connections to through the firewall for theright front of the truck:
Red = Right Front turn / marker lights
Yellow = Right front Headlight and starter connections
Black = Wiring for the alternator and Alt Gauge.

The tail lights (park lights) and dash lights are both connected to the built in circuit breaker in the Headlight switch. Either the switch has gone bad or someone has wired in some extra lights to the rear marker light circuit and it is to much for it.
Note: there are 2 built in circuit breakers in the light switch, one for the headlights and one for the park lights and dash light circuit.

Yes, that should be the correct light switch.

To change it:
You start by unhooking the battery.
Push that button on the switch and pull the knob out of the switch.
Unscrew the bezel and the switch will come loose from the dash.
Drop it down and unplug the wire harness from it.
Plug in the new switch and re-assemble!

Hope this helps!

[04stangman]

The relay on the passenger side is for marker / cab lights... I don't see any on your truck so not sure why you have it, unless it has a different bed or something on it.... The thing that was bolted to the left screw of it is the circuit breaker for the power to it. See this diagram for how it is hooked up normaly... http://www.fordification.com/images/sch ... arkers.jpg

The Red, Yellow, and Black connectors are for the connections to through the firewall for theright front of the truck:
Red = Right Front turn / marker lights
Yellow = Right front Headlight and starter connections
Black = Wiring for the alternator and Alt Gauge.

The tail lights (park lights) and dash lights are both connected to the built in circuit breaker in the Headlight switch. Either the switch has gone bad or someone has wired in some extra lights to the rear marker light circuit and it is to much for it.
Note: there are 2 built in circuit breakers in the light switch, one for the headlights and one for the park lights and dash light circuit.

Yes, that should be the correct light switch.

To change it:
You start by unhooking the battery.
Push that button on the switch and pull the knob out of the switch.
Unscrew the bezel and the switch will come loose from the dash.
Drop it down and unplug the wire harness from it.
Plug in the new switch and re-assemble!

Hope this helps!

Holy Shi#$ Thunderfoot, thats what I am talking about! I cant begin to thank you enough for your help. 1 more question,

the bezel you are talking about, is that on the front outside of the dash, or underneath on the rear of the dash?

On a skill level from 1-10 10 being the hardest how would rate it?

[Thunderfoot]

No Problem!

After you pull the knob out you use a w-i-d-e flat blade screwdriver and unscrew the center of the bezel out and the switch will come out. This center part is like a bolt with a hole in it for the knob shaft and it screws into the switch pulling it into the back of the dash...

I would rate this at a 3 maybe... only because when you go to push that release button for the knob, and go to pull the knob out, sometimes it wants to be a little stubborn letting go, and you might have to go at it couple of times to get it out (old stuff likes to stay put )
The wire plug into the the connector will be a little stiff as well, but you should be able to drop it down where you can see what your doing after you get it out of the dash.

Remember to disconnect the Negative cable on the battery before you start! and go for it.

[TheEskimo]

Just to throw it out there, I had almost the exact same problem with my '72 about two years ago. The same clicking and lights flickering/shutting off as you describe. I found that the rear lights were not grounding properly, and this is what was causing my problem.

Only thing different was when mine did that the headlights were cutting out as well. I did replace the headlight switch before I found that it was a bad ground, and never did find out what the relay was for let alone any one who carried them.

[willowbilly3]

Good advice eskimo, the first thing to do in any electrical problem is make sure you have food ground path.
Also the dimmer switch is a problem area. It isn't unusual to have a poor connection there, so I would remove and unplug that to inspect it too. Often the connector will need replaced.

[04stangman]

Good advice eskimo, the first thing to do in any electrical problem is make sure you have food ground path.
Also the dimmer switch is a problem area. It isn't unusual to have a poor connection there, so I would remove and unplug that to inspect it too. Often the connector will need replaced.

Hey Willow and Eskimo, Thanks for the help. But how do I check for a good ground, and where do I look and how do I know if I have a good ground? So, along with the switch, do I need to replace anything else, parts wise? I think the dimmer switch is on the main headlight switch right? I am going to attempt to replace the switch tomorrow. Press the button on the top, pull out the knob, unscrew the bezel and disconnect the plug........ I hope its that easy?

[bugser]

When you say flashing on and off, I assume that's a random thing?

[04stangman]

When you say flashing on and off, I assume that's a random thing?

Well, it just started one day, then I thought I fixed it, then it started again? I think it was either because I have a short somewhere, when the truck would move something either came loose, or some wires would touch? Or, something like the switch was getting hot. That is the reason that I thought it was fixed, maybe something was cooling off, then as soon as it got hot again it would start to act up again? I hate wiring!

[bugser]

Does it do it randomly or a timed pattern?

[04stangman]

Does it do it randomly or a timed pattern?

Randomly

[04stangman]

As usuall, you are al right about the light switch replacement. It was not that hard. So I changed it out this morning and so far its working. So, thanks again for all the help and advise!