Firewall Hole

[jamesroney]

Help!

I'm working on my 1970 Challenger, AC, 4 speed.

I found these pictures in the resource section, and I can't figure out this one hole. (red arrow below reverse lamp wire hole...)

Does anyone know what goes in this hole in a 70 Challenger? (It is used for my road lamps on my 70 'cuda...)

Thanks!

[anlauto]

My first thought would be the AC heater control cable  not really sure about that though

[jamesroney]

Hi Alan,

I thought about that, but convinced myself that the AC cable came out as per this pic.

But now I am wondering where the clutch switch wire goes when you have a Challenger with 4 speed ,and AC.

Thanks,
James.

[anlauto]

I'm not sure the reverse wire uses that large of a grommet in 1970  I think that hole in the yellow car could be for cruise control, and the small one below it the reverse light.

[headejm]

Could be for cruise control or something 4-speed related. My 1970 Challenger automatic w/ AC doesn't have either of the holes being discussed.

[jamesroney]

Hi Alan,

Really appreciate the help.

My reverse light wire grommet on the 1970 cuda is for sure 3/4 inch diameter.  Pics on the other thread show that the 1971 is larger than that at 1 inch.

I never thought of cruise control!  That might be the answer.

The AC cable is driving me crazy.  I have two cables.  one has an integrated 3/8 grommet, and the other does not.  My factory Air Challenger Convertible does not have any provision for the cable between the column and the apron.  The dimple is there...but no hole.
But I KNOW this car left the factory with A/C installed and functioning.  So I'm thinking that the non-grommet cable was routed thru one of the insulation retainer holes. 

I need to get out more...

[anlauto]

Yea, you're probably right....it's hard to tell the hole size in those photos

[EV2RTSE]

Cruise wasn't available with manual transmissions, so cruise wiring exited where reverse light wiring would.

[EV2RTSE]

The AC cable is driving me crazy.  I have two cables.  one has an integrated 3/8 grommet, and the other does not.  My factory Air Challenger Convertible does not have any provision for the cable between the column and the apron.  The dimple is there...but no hole.
But I KNOW this car left the factory with A/C installed and functioning.  So I'm thinking that the non-grommet cable was routed thru one of the insulation retainer holes. 

I recall hearing that there were two different length cables used in 1970 although I'm still not sure why there were two. Some were thinking it was power vs manual brakes, or build date but I'm still not sure what the reason really was. But it supposedly had to do with 2 different exit locations through the firewall. Also like you said, that one of the cables exited where an insulation nail would be; one cable had a grommet and one had its own sleeve.

edit: The other location for the cable to pass through was apparently over by the blower motor at the vacuum grommet:
https://board.moparts.org/ubbthreads/ubbthreads.php/topics/380244/1.html

[jamesroney]

Thanks to EV2RTSE for the link.  It appears that there are two cable LENGTHS, but I am also seeing two different grommet types.

Cut and pasted from the link:

The 70-71 parts book lists two cables for the 1970 model year.
71 inches long # 3431 215
74 inches long # 3431 339

I have two cables.  both are 71 inches long.  One has a grommet, one does not.  (pics attached.)  my Firewall has a hole under the blower motor with a provision for the cable.  So that question is solved for my car.  My temp cable routes under the blower motor, and is 71 inches long and does not use an integral grommet...but instead uses the 3-screw grommet for the AC vacuum source.

Anlauto has convinced me that the cruise control and reverse light use the same 3/4 inch hole.  Since they are mutually exclusive...that makes sense.

I still don't know what goes into the "cuda road lamp hole"  on a Challenger...but there's a couple of examples where that 3/8 inch diameter hole is present.