Tach wire

[kennyhbh]

installing a new MSD , my old one didn't have a wire for the tach. Were can located the wire that controls tach.With out ripping out the dash. Some were in the engine compartment. Chassis is 2006, looking were and what color the wire is. I order a msd 6420 and they ship a 6425 also any pros or cons on these 2 units.

[CWizard]

Remove the tachometer from the dash. There are two thumbscrews that secure a bracket onto the back of the tach, which holds it in the dash. Remove these and the bracket and pull the tach out the front of the dash. Connect the tach output from the ignition box to the white/black wire coming out of the plug connector on the back of the tach. Very easy.
MSD sent you a 6425 because they don't make a 6420 anymore. Check their web site. But if you really want a 6420, I have a used one that I'll be glad to sell you.
Good luck!

[kennyhbh]

Thanks c wizard ! Does that blk/white run into the engine compartment ? Like tap into there.

[DanMartin]

I like the Digital MSD (I converted from the old MSD when it died, but still got it repaired by them for a nominal fee).

The thee things like like best on the new model:
1) I like that you don't need the rev limiter 'pills' anymore...just set the unit and you're done.
2) I love the tach sweep on power-up. Snazzy, and shows you where your rev limiter is set to.
3) It's got a plug! Swapping out the unit is a piece of cake now (if needed)

I'm sure others may have reasons not to like, but so far I'm very happy with the Digital 6AL.