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Electrical dilemma....guru needed...long story


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Guest oldguy668
Posted

I just bought this little red 56 about 6 weeks ago. I didn't pay crazy money, and I expected there would be some things wrong that I'd find out about as I went along. So, I discovered that I need a valve job and the soft top needs some work, and most of the weatherstripping is like black sticky sawdust. That's the easy stuff.

I started to check out the wiring to see why the clock, dash lights, radio, lighter, etc had no power. The only things that seemed to work were the ignition, lights, horn, seats and windows. You know, the essential stuff.

Being pretty good at wiring, I crawled under the dash last week to take a look. Horrified is putting it lightly. Most of the dash harness was cooked to a crisp, and some imbecile had bypassed most of it by jumping off the big yellow feed wire (he also bypassed the fuses). Some of the wires were welded together and some were just melted into clumps.

I ended up pulling the dash out since it needs re-covering anyway. I sent the clock out for repair and got the tach and speedo cleaned up pretty nice. I got lucky over the weekend and scored a NOS dash harness with the same part number as mine, and that should be here in a couple of days.

So, here's the dilemma: All the wiring diagrams I have clearly show TWO circuit breakers on the cowl panel, one for the seats and one for the windows. My car has only one breaker, and both the seats and windows tie into it. There is no evidence (like holes) that there ever was a second breaker. Not really a big deal since it's unlikely that any of them will be used simultaneously. My guess is that the car did not get built with both power options so it did not get wired for them. Nevertheless, wanting to do it right, I want to install the second breaker. But, the diagrams do not clearly show the power path for the seats. The windows are easy (Big yellow wire to the "safe relay" and back to the BAT terminal on the breaker, then split to each window harness), but the seats look like they have two 12V feeds, which is causing my head to spin (not comfortable at my age).

If anyone has some insight into the gordian knot-like seat harness connections at the cowl, I'd really appreciate a little coaching

Posted

Hi Oldguy668, do you mean 2 relays on the firewall? From what I can tell there is one relay on the firewall under the hood for the power windows. The wiring for the power seat is under the dash. If I were you I would also get the wiring harnesses for the power windows and the power seat. It would be easier to figure out what connects with what with all new wires that are the correct color. Do you have a copy of the electrical installation manual for the T-Bird? It is available from CTCI and will be helpful to you putting things back together. Also, you may want to paint the back side of the dashboard white. It definitely helps in putting things back together. I hope this helps.

Guest oldguy668
Posted

The window circuit is easy. There's a feed from the BAT side of the start relay through the "safe relay" (that one just kills the window circuit when the key is off) then to the 30 amp breaker on the cowl panel. From the breaker, each door gets a power feed (red-blue). Here's where I get lost. The Electrical Assembly Manual (Page FS95) shows a feed from the ACC terminal of the ignition switch through a 15A breaker (location unknown) to the seat switch assembly. However, it also shows a feed from the BAT side of the starter relay through a 30A breaker to both seat motor relays. Since I am rewiring the dash harness, I need to know what the deal is with the wire that goes to the seat switch. Is it part of the dash harness or the door harness?

Posted

I think I have the answer for you. Since both the power windows and power seats were optional in 1956 a car could be ordered with one, both, or neither. The page you refer to only shows the seat wiring. Your car was obviously ordered with both PW and PS. What that means to you is that you would need to have a wiring diagram that shows both of the items installed together, rather than each item installed separately. I think you can see that on page FS881. It is titled Installation-Electric Window & Seat Regulator. To wire it all up I think you will need the following harnesses to go with the main one, 14630B, 14631D, and 14679. One last thought, if you can find another 56 that has all the wiring in place you can check what you are doing against that.

Guest oldguy668
Posted

Thanks for the tip, Lew. I have that page in front of me and I think it's starting to clear my mental cobwebs.

Guest oldguy668
Posted

One last bit of help and I'll have this baby running by the weekend. When I removed the dash to replace the harness, this section of daisy-chained grounds fell out.

post-92667-143141893157_thumb.jpg

I haven't been able to find it on any schematics, but it would be helpful if I knew which 5 or 6 things it connected to. It appears to be part number 14590.

Posted

If it is 14590 it has to do with the door jamb switches and the courtesy light. 14590 is shown on chart FS701. I can't tell based on the chart if it is the set of wires you have there, but is certainly could be. It might be worth your time to call the CASCO tech line and ask them. They would certainly know. Good luck!

Guest oldguy668
Posted

FS701 shows that it's a daisy-chain ground that runs to the speaker grille, speedo pod, tach, and a couple of spots on the dash. Looks like I'm all set, Lew. Thanks for pointing me in the right direction.

  • 3 weeks later...
Posted

Hi Guys,

I'm new with the Earlybird Forum here, I'm a 38 Buickguy and normally here in the Prewar Buick Thread but my Girl had bought last year a very nice restored 6V- Plus on Ground '54 pre Series - Bird with both Options,E-Seats and P-Windows and I had wondering for the Extra Wiring and Fuse. Now you explain it to me.

I will read more here for learn more Internas of the especially 6 V Earlybird.

Thanks Guys

Thanks Guys.

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