Dash Lights

CableguyJJS3 · 2013-04-22 22:50

Ok another question on this Ranchero. I have all the lights in the car working properly, head lights and tailights turn signals and such. My question is on the dash lights now. With the key off I can make the head lights and tailights work as they should. However I have no dash lights until I turn the key to the on position. And then no matter what position the headlight switch is in the dash lights are on. I would think the dash lights shouldn't come on until the headlight switch is pulled out. Also turning the knob has no change on the dash lights at all, they are always on as bright as can be. I have checked over the wiring and compared it to all the diagrams I have and everything seems to be hooked up correctly, but am I missing something here?? I have 2 headlight switches, no difference in either switch, could it all just be in the switch itself? Thanks for the help guys. Jim

Ford Blue blood · 2013-04-23 07:10

The dash lights are powered through the head light switch via the big resistor at the front of the switch. The terminal on the switch that the dash lights are powered off of is "I". The wire is Blue/red stripe. The power source for the dash lights is through the head light switch and as you thought the dash lights should come on when the switch is pulled. All the dash lights along with the radio, heater and clock are fed off this terminal. You have a "switched 12V plugged in some where and the correct blue/red wire from the switch terminal I is not hooked up.

ROKuberski · 2013-04-23 08:47

Just a comment on the headlight switch. This is removable and likely needs cleaning. My switch worked okay to turn on the headlights, but the rheostat function was very erratic. As I turned the knob left and right the dash lights would go from off, bright, dim and in no particular order and some areas there was no current flow at all. Once I cleaned the switch with a product called DEOXIT, an electronics parts cleaner, the switch works like new.

Rich

CableguyJJS3 · 2013-04-23 12:48

Allright, i'll go back through everything again. I have the entire dash harness seperated out of the main harness, so I know I have that isolated, and it is on the I pin, or so I thought, I'll have to double check. I just scored a intact harness to help with this problem(shout out and big thanks to Rich for that) so I'm hopefull I can figure this out. Now I just need to figure out how I have a switched 12v creeping into the line. As far as I cvan tell there nothing there. But again, now that I know how it's supposed to work properly, hopefully I can sort this out. I'm about over wiring this car, I need to get this back together and get on with mechainicals.

ROKuberski · 2013-04-23 13:21

The only time power is to the instrument panel lights is when the headlight switch is pulled out to either the first or second stop. Panel lights are independent of the ignition switch position. Power to the instrument panel lights comes from headlight switch off of a terminal with the rheostat using a #18 wire that has blue insulation with a red band. If your car is pointing north, this terminal is on the south end of the switch, mounted on top of the switch. Access sucks!

Do you have a wiring diagram? If not, I can email one to you. It shows the color codes on the wires too. The cover says it is for Ford and Thunderbird, no mention is made of the Ranchero, but it might be identical.

Rich

CableguyJJS3 · 2013-04-23 15:25

I have a full shop manual for the car which is 57 specific plus a wiring diagram I got from a classic Ford parts dealer here local.It's not much, just basically a blow up of the diagrams from the manual, but it helps have mulitple diagrams in front of me at once. I just wish I have a fulll car diagram to see how each circuit interacts with one another. But either way, I must have something messed up, I guess some more testing is in order here.

BWhitmore · 2013-04-23 16:21

I will find the wiring diagram that came with my under dash harness and post it later today. This diagram was excellent. I wired my Ranchero using this diagram.

BWhitmore · 2013-04-23 16:39

Ranchero Wiring Diagram (underdash). Used when installing a new underdash harness made by Bauer Electronics in Oregon. Ignore the check marks, they were made by me when installing the harness. Bauer Electronics is also very helpful over the phone. I do not have their number, but an internet search will find them.

CableguyJJS3 · 2013-04-23 17:01

Thanks for that. Thats a prety good diagram, I'll have to print that out and and that to the ones I have while I try to sort this out. Thanks for the help guys.

BWhitmore · 2013-04-23 17:32

I forgot to mention that this diagram includes a neutral safety switch for auto trans cars, For a manual trans car you just attach the two wires together that would normally go to the neutral safety switch. Another possibility for your dash light problem is you may have the oil pressure light in the wrong hole in the back of the dash. This light will come on when the key is turned on and is bright and if in the wrong hole will light up the dash. The light will go out when the engine is running and you have good oil pressure.

CableguyJJS3 · 2013-04-23 20:33

Ok I'll admit, I'm an idiot. What I thought was dashlights was exactly that, oil pressure and gen lights lighting up the dash. I forgot I needed to have the dash cluster grounded, and as I have the whole thing laying out while I try to fix everything and get it wired right, it's obviously not grounded. So hooked up a ground wire and bang everything lights up and works correctly. so time to put the harness back together and get everything installed so I can close up the interior. Thanks guys.

RICH MUISE · 2013-04-23 21:35

Good call Bill!

BWhitmore · 2013-04-23 22:04

Cable guy -I did exactly the same thing. I am glad it worked out for you.

Tom S · 2013-04-26 14:10

I can't seem to find the amp rating for the fuse on the back of the light switch. Anybody know what it is?

BWhitmore · 2013-04-26 16:10

7 1/2 amp fuse.

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Dash Lights