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RE: 75 electronic overdrive schematic

To: "'jhaeg'" <haeg1@mninter.net>, "'6 pack list'"
Subject: RE: 75 electronic overdrive schematic
From: "Jim Davis" <jdavis344@bellsouth.net>
Date: Sat, 1 Nov 2003 19:20:45 -0500
My '75 TR6 is wired per Dan's manual in that there are only 2 relays
fitted, 1 for the starter and 1 for the horns. The o/d has no relay in
my car. If your car has a relay for the o/d it may have been installed
by a PO, but I doubt the factory fitted it. This may be the source of
your confusion.

Jim Davis
Fortson, GA
CF38690UO
 

Does anyone have an electronic schematic for a 75 TR6 electronic
overdrive system? (web link or e-mail) If no, a description of the
circuit would probably work just as well.

Note: The Bentley manual is missing the 75 and 76 version, and the 75
isn't matching the earlier design. Does the new Haynes manual have this
schematic?
Note: Dan Masters Electrical book has nice looking schematics for each
year, but none of the overdrive schematics on the later cars are
correct. They just have a switch turning on an electric overdrive
solenoid. This is the first time I've used this manual to actually
troubleshoot, and I'm a little disappointed.

My problem: The fuse supplying power to the GREEN wires is blowing. The
fuse will not blow if I disconnect the overdrive on/off switch.

Here is what I can figure out:
-C1 and C4 are the overdrive relay contacts.
-W1 and W2 are the overdrive relay windings.
- One side of the overdrive switch is tied directly to the GREEN
switched B+ line.
- The heavy gauge brown wires connect to C1, and are switched B+.
- The C4 wires (WHT/RED and WHT/YEL) have continuity between them, and
seem to be the electrical load that gets turned on by the relay. One
should go to the overdrive solenoid, but what does the other one do?
- The wire at W2 is also (WHT/RED), and has continuity with the
(WHT/RED) electrical load wire. This looks to be some type of latching
circuit, but I'm going to need a real schematic to proceed.

Thanks for your time,

John H. in Minneapolis.




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