Topic: 65 Rally Pac Install

[midlife]

Here are pictures of my Rally Pac from a previous thread: http://www.concoursmustang.com/forum/index.php?topic=3615.msg19444#msg19444  Pictures don't show tach wires.

Aside from the wires on the rally pac, only other wires are on the under dash harness. I have an original harness and it has the same number and type of connectors as the reproduction shown in the picture at the top of the post. Is the connector you're referring to that mates with the pink resistor wire from the under dash harness or from the rally pac? Female bullet connector would be coming from the tach/rp itself.

[Chris]

I installed the Rally Pac today, the steps I took are below. The Rally Pac works fine but my clock only works when I pull the lights on.

Tach side wires:
1) Look at the pictures below. The wires coming out of the Rally Pac on the left are the Tach wires. The short blue and red connector with black end plugs into the three-hole red connector from the underdash harness.

2) The red wire from the Rally Pac will go and plug into the connector from the ignition switch. You have to remove the instrument cluster to get to the wires for the ignition switch. You unplug the existing pink resistor wire from the ignition switch connector. You then plug in the red wire from the Rally Pac tach.

3) The black wire with connector from the Rally Pac tach will go under the dash and connect with the pink resistor wire just unplugged from the ignition switch.

Clock side wires:
1) Look at picture 3. The red stripe wire from the clock (my wire has faded, can make out red stripe) connects to the blue/black wire with blue connector from the underdash wiring harness.

2) The black wire from the clock conncets to the black wire with black connector from the underdash harness.

3) The remaining clock wire (mine faded blue with black stripe) connects into the three-hole red plug connector from the underdash harness.

Remaining underdash harness wires:
1) The black wire with circle connector is the clock ground and connects to the existing screw on the metal pillar behind the instrument cluster.

2) The black/red wire from the harness connects into the existing three-hole connector behind the dash (mine is three-hole black connector).

3) The red wire with green connector from the underdash harness is not used.

4) This leaves the blue wire green/yellow wire splitter that goes over to the courtsey light conncetion in the door jam. After removing the scuff plate and side kick panel to get at the wiring, you pry out the courtsey light and unplug the existing green/yellow stripe wire from the back of the light. Plug in the blue wire into the back of the courtsey light and then plug the green/yellow wire into the conncetor of the short green/yellow wire from the harness.

After putting everything back together, my Rally Pac worked fine (picture 7). The rpm is at 1000 at idle and in Park. When in gear the rpm drops to about 500-600 rpm. The clock works but it only runs when the lights are turned on...so I did something wrong with the clock but have not figured out what yet. I may have plugged in something incorrectly at the courtsey light.

[jwc66k]

Don't overlook a bad connection inside the Rally Pac.
Jim

[midlife]

1) Look at picture 3. The red stripe wire from the clock (my wire has faded, can make out red stripe) connects to the blue/black wire with blue connector from the underdash wiring harness.

Nope.  Blue/black wires are for courtesy lights and are only on when the door is opened or the interior courtesy lights are on via the headlight switch.  This wire has to go to a green/yellow wire.  This wire color is always on and fused.

4) This leaves the blue wire green/yellow wire splitter that goes over to the courtsey light conncetion in the door jam. After removing the scuff plate and side kick panel to get at the wiring, you pry out the courtsey light and unplug the existing green/yellow stripe wire from the back of the light. Plug in the blue wire into the back of the courtsey light and then plug the green/yellow wire into the conncetor of the short green/yellow wire from the harness.

That seems correct, and I can't explain why your clock only works when it does.  Try inserting the male bullet into the 90* cigarette lighter bullet; the clock should run at all times.

[Chris]

I swapped two wires and the clock now runs all the time. Referencing picture 3, I pulled the blue wire from the red three-hole connector and connected it to the blue female connector on the wiring harness. The yellow wire with red stripe was moved to the red three hole connector. Everything seems to operate correctly now.

If the clock is running all the time, is the voltage it's pulling from the battery significant? Any chance of it draining the battery?

[midlife]

Typical draw of an original rally pac clock is about 15 milliamps; too small to worry about with current draw. 

You can measure the current draw by using a digital volt-ohm meter.  Set it to DC current (not your typical set-up for cables on the meter), disconnect the negative battery post and measure current (with the engine off and everything turned off) between the negative battery post and the disconnected cable terminal.

[jwc66k]

Typical draw of an original rally pac clock is about 15 milliamps; too small to worry about with current draw. 

Probably true, but it's 24 hours a day, 7 days a week, and it adds up if you don't drive or at least start your car weekly. I couldn't figure out why my batteries (note plural) kept going down, they came back when I used a trickle charger regularly, and it turned out to be the clock. Eventually you will install a battery disconnect switch (the kind with a green knob) which solves that problem. (If you have a radio with a memory circuit, wrong forum.)
Jim

[midlife]

Probably true, but it's 24 hours a day, 7 days a week, and it adds up if you don't drive or at least start your car weekly. I couldn't figure out why my batteries (note plural) kept going down, they came back when I used a trickle charger regularly, and it turned out to be the clock. Eventually you will install a battery disconnect switch (the kind with a green knob) which solves that problem. (If you have a radio with a memory circuit, wrong forum.)
Jim

I agree 100%.
Vintage cars that aren't driven regularly at least once every two weeks or so should have their batteries disconnected for this very reason.  You can probably go a bit longer (think of folks who leave their cars at the airport), but why chance it? 

[zray]

Not quite true.  The tach consists of two fundamental parts: a transformer on the input side and a gauge on the output side.  The gauge can fail but the transformer can still be good and the car will run.  If the transformer fails, then the gauge will read nothing and the signal to the coil will also fail.

I hear frequently how risky it is to run the factory tach, that you will get "stranded" when it dies, etc. but I've yet to run across anyone that it has actually happened to n he past 45 years I've been driving and working on old Fords. It happens, sure. But so does getting killed by lightening or winning the lottery. Just not very often.

Z.

[Richard P.]

+ 1 Zray, I'm running rally pacs that are 48 and 49 years old and haven't had any problems. In the event that I do have problems I'll simply disconnect the rally pac from the system and drive on.

[zray]

+ 1 Zray, I'm running rally pacs that are 48 and 49 years old and haven't had any problems. In the event that I do have problems I'll simply disconnect the rally pac from the system and drive on.

that's my view.  and even if you can't access the wiring from under the dash, it takes all of 2 minutes to remove the instrument panel and have clear access to the tach / ignition switch wiring circuit.  I wouldn't call that kind of repair "being stranded".

Z.