1969 sequential board replacement

[66thunder]

Recently bought a replacement board for my directionals not working.  Was advised by a parts supplier that if i replaced the can flasher under the dash with an electronic flasher box i could just yank the 4 relays as the new board is not wired for them anyway.  Anyone heard of this?

[Bob Gaines]

Recently bought a replacement board for my directionals not working.  Was advised by a parts supplier that if i replaced the can flasher under the dash with an electronic flasher box i could just yank the 4 relays as the new board is not wired for them anyway.  Anyone heard of this?

4 relays on top of the black plastic box was never used on 69/70 Shelby. I believe that is 71 Cougar but not sure in any event not Shelby ether.

[66thunder]

thanks for the help, i replaced just the flasher can with the electronic unit, directionals now working.  Just left the 4 relays attached as it was, don't know why anybody put them in.

[Bob Gaines]

thanks for the help, i replaced just the flasher can with the electronic unit, directionals now working.  Just left the 4 relays attached as it was, don't know why anybody put them in.

FYI that is because the entire black box unit was replaced with the unit that had the relays on top. The plug wiring is integrated with the relay wiring.It was made that way. They were not added.

[Bob Gaines]

This is what was suppose to be in a 69/70 Shelby. Notice the different wiring at the plugs. The unit with the relays on top is most likely from a 71 Cougar originally 

[Coralsnake]

Yes and now that you continue to change out parts you are creating more incompatability issues. It may work temporarily, but eventually its going to be even harder for someone to troubleshoot and resolve.

[66thunder]

ok. i guess i'll swap just the new repo board in and take out the cougar one with the relays and see if it still works
thanks guys

[cougarsunlimited]

The addition of the four relays to the sequential controller boards was a production change as of 1/1/70 for Cougars and Thunderbirds. The change was an attempt to make the rear lights brighter to meet 1970 Federal lighting standards. The relays eliminated the ~ 1V voltage drop across the SCR transistors used in the original sequential boards thus theoretically making the lights brighter. The under dash turn signal flasher can was changed to a green D0WY-13350-C at the same time to accommodate the increased current draw and maintain the correct flashing rate.

Since all the 1969-70 Shelby Mustangs were built prior to 1/1/70, none came with a sequential controller with relays. However, it was the service part available from Ford. Unfortunately, the relays are not reliable. The contact spring arm on these relays eventually work hardens and breaks off. When the arm breaks off, it either shorts the light on or renders the relay ineffective.

The current reproduction sequential controller boards do not use relays and do not have a provision for adding them to improve long term reliability.

Vic Yarberry
Cougars Unlimited LLC
www.cougarsunlimited.net

[Cobrask8]

I was going to add the info Vic presented, as he is right in both the service replacement for the sequential unit, and the voltage drop caused by the internal components.

BTW - The relays used were a horn relay from early 60's ford cars.