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1968 Tach dash and idiot light wiring

lnevill

Well-known member
Joined
Jun 25, 2013
Messages
64
I started a post last week on a problem I was having with Bonnie and Clyde's Oil Pressure idiot light. Now that I have this issue resolved and understood, I thought it would be best to re-post and clear up some of the misleading information I put in that post!!

1. I was not able to find a schematic from Ford for the tach dash wiring. There is a supplement that shows how to wire in the tach itself (hot wire in series with coil), but nothing on the Alt and OP idiot lights.

2. The schematic for the non-tach car does not help (this is where I went wrong). This schematic shows the OP power source as the constant voltage regulator. It is for a guage, but it is not for an idiot light. As RVRTRASH (Steve) tried to point out in the previous post, the source of the power for the OP light is 12v, and in fact is the same wire that feeds the dual brake warning light.

3. The wire colors stamped by each socket on the back of the dash itself are the best source of knowing which wires go where. When comparing to the non-tach schematic, I thought wires had been swapped when the harness was restored, but the colors match what is stamped on the panel.

Here are the wire colors for the tach dash harness:

Oil Pressure hot (12v) = Red/Yellow
Oil Pressure sender = White/Red
Alt hot (12v) = Black/Green
Alt sender = Yellow/black
Brake hot (12v) = Red/Yellow
Brake sender = Violet/white

My constant voltage regulator was indeed fried, but I don't think it had anything to do with this issue. I found the 12v lead that feeds the red/yellow wire to be broken at the connector. Fixed that, replaced the VR and all is good!

Thanks,
Lee
 

dalorzo_f

Well-known member
Joined
Jan 7, 2006
Messages
1,886
Location
Brisbane Australia
Lee, great info and a favour to ask.

I have worked up a '68 master color coded wiring diagram and have some info on the lights noted, but not a lot (as you note not well documented). Would you be able to send a sketch of what you found so I can add it to the diagram I have developed??? Or I can send a copy that you can mark up or provide comment on...???

P.S. Note to all, if you are thinking of buying the advertised "color coded" wiring diagrams be aware they do not include the one you would want most, the primary "whole car" 2 pager. It only includes the "per system" ones... IMO not worth the money...
 
OP
OP
lnevill

lnevill

Well-known member
Joined
Jun 25, 2013
Messages
64
Send me a copy of what you have so I know exactly what you are looking for and I'll be happy to add the information I've learned.

Lee
 
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