Original E body Rally Dash Wiring Harness

[mccannix]

Dug a couple old harnesses out.
1970 only on the left with 3 prong horn relay provision and 71 up on the right with 4.
70 relay only is 2926327 and 71 and up is 3513206

[VCODE]

Dug a couple old harnesses out.
1970 only on the left with 3 prong horn relay provision and 71 up on the right with 4.
70 relay only is 2926327 and 71 and up is 3513206

@mccannix
Says it all. Pictures worth a thousand words

[erik70rt]

Here is a pic of the horn relay.  Definitely not a 70, but it also definitely doesn't protrude from the firewall. 

[RJChallenger]

@erik70rt that's the same harness as in my 5-70 A66 Challenger that I have had since 82.

[anlauto]

I agree with VCode .
Pull the horn relay out...3 terminals and its a 1970, 4 terminals and up would be 71 and up.
Rearding the dimmer switch plastic, someone could have easily exchanged the plastic base.

This is the best answer

[erik70rt]

Do I have to make any modifications to use it for my '70 Challenger convertible? 

[198D13]

I agree with VCode .
Pull the horn relay out...3 terminals and its a 1970, 4 terminals and up would be 71 and up.
Rearding the dimmer switch plastic, someone could have easily exchanged the plastic base.

This is the best answer

The "2' series part number is 1970, the "3" series part number is 1971 and later, stamped into the fuse box holder.
I think that is a fair answer too.