Wiring help, please???

[cruiksdr]

I just got a newer tach (I think it's a 71 or 72). It has a 7 prong outlet on the back where my old (68 911L) one had 3. Any help on on the wiring (eg, which prong is for what) would be greatly appreciated. The wiring diagrams I've seen don't seem to match this configuration.



Thanks!

[filou]

what brand is it ??? Can you do any resistance and continuity testing with
digital meter ??? Can you a least find the ground connection ???
Trying to help. Maybe some of the outlets are double, which means 2 connectors for same usage.
Trying to help.
Filou.

[cruiksdr]

Originally posted by filou
what brand is it ??? Can you do any resistance and continuity testing with digital meter ??? Can you a least find the ground connection ??? Trying to help. Maybe some of the outlets are double, which means 2 connectors for same usage.
Trying to help.
Filou.

It's a VDO tach that the seller said was from a 72 911. I don't have a digital meter and electrical is my weakest area. I do have a basic ohm/voltage meter. To test for a ground, would I look for a circuit between a prong and the tach housing? I guess I could also test to see if there are circuits between the various connectors using the ohm meter?

[Tim Polzin]

I've never seen a connector like that on the back of a 911 tach. Certainly not a standard 72 model. Is there a Porsche part number on it?

Tim

[filou]

Exactly it. Start to look for ground with the meter placed on Ohmeter function. Any continuity between one of the prong and the housing will be the ground. Try to see if any of the others prongs have relationship between one and another. Like i said, maybe some of the prongs available are double within the same connection. So two prongs might have continuity, one with another.
Keep us posted.
Filou.

[304065]

1971 tach has FOUR prongs.

On the back of the tach there should be a blue stamp with the date in a circle.

Can you post a picture of the FRONT?

[304065]

Check the wiring diagram located in "Elec Diagrams" on the pelican home page.

[Early_S_Man]

Daniel,

That is an '84 - '89 Carrera tach ... are there any terminal numbers in the connector next to the pins???

#1 Black -- ground return/shield from DME unit
#2 Black/Violet -- TD tach signal from DME unit

#3 Brn/Red -- speedometer
#4 Gray -- exterior lights or wiper/washer system

#5 Red/Black -- switched +12 Volt power
#6 Brown -- Ground

#7 -- not used
#8 -- not used

[cruiksdr]

Originally posted by Early_S_Man
Daniel,

That is an '84 - '89 Carrera tach ... are there any terminal numbers in the connector next to the pins???

#1 Black -- ground return/shield from DME unit
#2 Black/Violet -- TD tach signal from DME unit

#3 Brn/Red -- speedometer
#4 Gray -- exterior lights or wiper/washer system

#5 Red/Black -- switched +12 Volt power
#6 Brown -- Ground

#7 -- not used
#8 -- not used

Thanks! That helps alot. It does have pin numbers so this should be easy. However, since I don't have a DME, is it safe to assume that the #2 would go to my CD Box tach trigger (Crane HI6)??

[Early_S_Man]

Daniel,

Yes, the #2 terminal is what needs the tach signal ... hopefully the Crane unit can provide the proper signal!

[cruiksdr]

Originally posted by Early_S_Man
Daniel,

Yes, the #2 terminal is what needs the tach signal ... hopefully the Crane unit can provide the proper signal!

Hey, thanks!! I finally got out there and got it wired according to your guide, and it works great.