Topic: Rally Pac Lights Blowing Instrument Light Fuse

[drummingrocks]

I've got a reproduction Rally Pac on my '65 convertible.  Ever since I bought the unit 5-6 years ago, I've never been able to make the rally pac lights come on at night with the regular instrument cluster lights.  Things work great until I plug in the leads for the rally pac lights; the minute the rally pac light leads are plugged into the underdash harness, it immediately blows the instrument light fuse in the fuse panel.  It acts exactly like there's a dead short somewhere.

I seem to remember hearing that there was a run of reproduction rally pacs made with the illumination wires crossed.  With the hot wire going to ground and the ground wire going to hot, it would yield a short exactly like I'm experiencing.

Has anyone run into this yet?  I've taken the Rally Pac out of the car and have it disassembled on the workbench.  I expected to find an obvious wiring mistake, but so far, nothing sticks out.  Again, the regular instrument lights light up fine until the rally pac is plugged in, leading me to think that there's a problem in the rally pac itself.

Thanks for any help!

[jwc66k]

Why don't you take the Rally Pac apart and find out what the problem is? Most fuse blowing problems are simple, a pinched wire during assembly. My contibution to the fuse industry's increase in production was a horn mounting nut shorting the power feed to my right hand fog light.
Jim

[drummingrocks]

It's in several pieces on my workbench.  Like I said, I expected to see something obvious, like you said, a pinched wire or a hot wire to ground.  But there's nothing obviously wrong.

[midlife]

Lamps require a power in (blue/red wire, female on main harness, male on RP side), and a ground wire (black, male on main harness, female on RP side). 

Have you tried plugging in the lamp power connector without a bulb in the RP?  If it does blow, that says there's an internal short or wiring issue.  If it doesn't blow, it is somewhere in the lamp socket itself.

[7Lscjracer]

I'm waiting on a rally pak for a 66.
My parts guy tells me 90 to 120 days for the new repro that supercedes the old due to an issue we're not clear on.
I asked for the Scott Drake one since the ignition is Pertronix.
It doesn't have Mustang or Ford on the gauge faces since they didn't write Ford a check.
There's an exact repro out there that does, and it uses the factory dash hookup too, but it's no good with Pertronix.

[drummingrocks]

I'm waiting on a rally pak for a 66.
My parts guy tells me 90 to 120 days for the new repro that supercedes the old due to an issue we're not clear on.
I asked for the Scott Drake one since the ignition is Pertronix.
It doesn't have Mustang or Ford on the gauge faces since they didn't write Ford a check.
There's an exact repro out there that does, and it uses the factory dash hookup too, but it's no good with Pertronix.

I'll have to double check here, as I'm going off of memory, but I know my rally pac says "Mustang" on the tachometer face, and I'm running it with a Pertronix ignition.  I seem to remember that I just had to run a single wire to one side of the coil to feed the tachometer gauge.  Again, let me check, I set this up 5-6 years ago, and I've looked at and worked on a LOT of Mustangs since then!

[7Lscjracer]

I found the tech article again I remember reading awhile back that gives the lowdown on the different rally pacs:
http://www.sacramento-mustang.com/Newsletter/rally_pac/tachometer.shtml

Here are installation instructions:
http://www.cjponyparts.com/tech-rally-pac/a/145/

[buckeyeresto]

had one of these onetime and the light socket was causing the short

[drummingrocks]

had one of these onetime and the light socket was causing the short

I wonder if that wasn't the problem with mine also.  After getting it apart and studying a bit more, I noticed that the light socket on one of the gauges was touching a metal mounting post.

[NEFaurora]

"and it uses the factory dash hookup too, but it's no good with Pertronix."

Not true.

The OVAL INDUSTRIES Rally-Pac is supposed to work correctly with the Pertronix 1 only.  Other Electronic ignition setups will not work with it though like Mallory, Accel, MSD or Pertronix II or III.

Tony Kovar
1966 Sprint 200 Registry
MCA#70001

[sjackson]

Drummingrocks,

Hello,  I am also having your same issue.  I just bought a repro Rally Pack and everything works, EXCEPT the light on the tachometer side.  When I plug that wire in it blows the fuse every time just as you are saying.  Funny thing is that the light on the clock side works with no issue.  Only when I plug in the tach light does it blow the fuse.  I have not taken the tach apart and don't want to since I just bought the thing 3 weeks ago.  I'm half tempted to take it back and get a new one, but I've already had it painted to match the dash.

My question is was it your light socket your problem? Did you ever get yours working?  I'd hate to have to take it apart if that won't solve the problem. I am almost positive that the new Rally Pack is the problem.  Any help would be great, this has been extremely frustrating.

THANKS!

[drummingrocks]

Neither the clock nor the tach lights ever worked on mine.  I took mine entirely apart, hoping to find something obviously wrong in the wiring, but I never saw anything.  When I put it all back together, it did the same exact thing.  I'm starting to wonder if the wiring is reversed--if there's a power wire going to ground and a ground wire going to power.  It has to be something like that since it's a dead short, and it immediately pops the fuse when plugged in.

So far, I haven't had time to mess with mine again; I've just been leaving the light wiring unplugged and tucked up around the steering column.  Good luck with yours, and let us know if you happen to fix it.  If I have time to dig into mine again and do happen to fix it, I'll post the fix here.

Thanks!