78 Speedometer Inop
Thread Starter
Cruising
Joined: Jul 2010
Posts: 10
Likes: 0
78 Speedometer Inop
I have been figuring things out on my 78 that I have recently acquired. (First vette'..../golf clap) Little by little its becoming the car I would expect it to be, which is a feat seeing that I am not by any description a mechanic. I have been relying on friends that are for the most part. One issue that I still need to figure out is that the Speedo is not working at all. I am starting to get tired of guessing using the Tac, so I would like to get it figured out. I am assuming its just unplugged under the steering / dash, but I have no clue what I am looking for. I was able to locate three connectors that appear to just be hanging and unconnected, but even if I knew what they were, I don't see anywhere they are suppose to be plugged in. I was wondering if anyone could give me some direction. Maybe pics or diagrams even. I was able to snap some pretty bad shots, not sure if they are any help. One connector is a small blue (Molex?) style connector, another is a standard black connector and the other was a fairly long white connector (or hub?) that barly sneaks out from behind the ?"fuse box"? that sits all the way forward. Am I even warm?
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
wc5b,
Can't really tell from your pictures but I too have a 78' and will go look for the 4 wire white connector. This web site has all the wiring diagrams for 78' which you should find usefull. The speedo is cable driven so the cable may be broken.
Gary
http://www.corvetteforum.net/c3/tune...l/index6.shtml
Just looked, the only 4 wire white connector I saw was fastened to the right side of the fuse box and gets the headlight/key reminder buzzer plugged into it.
Can't really tell from your pictures but I too have a 78' and will go look for the 4 wire white connector. This web site has all the wiring diagrams for 78' which you should find usefull. The speedo is cable driven so the cable may be broken.
Gary
http://www.corvetteforum.net/c3/tune...l/index6.shtml
Just looked, the only 4 wire white connector I saw was fastened to the right side of the fuse box and gets the headlight/key reminder buzzer plugged into it.
Last edited by Duke94; Aug 9, 2010 at 06:19 PM.
Le Mans Master
Joined: Sep 2002
Posts: 5,236
Likes: 898
From: Myrtle Beach SC
One issue that I still need to figure out is that the Speedo is not working at all. I am assuming its just unplugged under the steering / dash, but I have no clue what I am looking for. I was able to locate three connectors that appear to just be hanging and unconnected, but even if I knew what they were, I don't see anywhere they are suppose to be plugged in. I was wondering if anyone could give me some direction. Maybe pics or diagrams even. I was able to snap some pretty bad shots, not sure if they are any help. One connector is a small blue (Molex?) style connector, another is a standard black connector and the other was a fairly long white connector (or hub?) that barly sneaks out from behind the ?"fuse box"? that sits all the way forward. Am I even warm?
My first question is what else in the dash is not working...those plugs could be contributing to other electrical problems and may not be a factor for the faulty speedo. The speedo has a floppy circuit board that could be a source of your problem but it won't help to replace it without knowing all is connected and operational.
I've got a 78, that I've working on the electrical stuff and doing the type troubleshooting we are describing here. I can look check out the driver's side dash area and look for the connectors you describe above. It would be helpful if you could precisely describe the location of those connectors you're describing. So when you say "hanging" are they hanging from the steering column harness? Or, are they hanging from a dash harness that appears from under the dash area or is it a dash narness that comes out from the firewall?
Anyway...keep us posted. I've got a series of diagrams as well so can follow along.
