When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
77 Corvette - Dash wiring identification help needed
Hi all. I just purchased a 77 corvette and having some electric al issues. I’m not sure what to mention first.
So...I noticed the none of the dash lights work. After watching a lot of YouTube videos I bravely took able the center cluster out.
ISSUE 1 - It looks like someone has removed all light bulbs and sockets. The tach and speedo also has bulbs pulled. I’ve also been noticing the battery drain after a week or so.
ISSUE 2 - Several wires are not connected to anything and the manuals I’ve purchased not helping me find out what they go to. This is what I guess I need help on first. See pics.
I would be very grateful for any help on this. Thanks in advance!!
Photo 1. If the wire colors are black and grey, on the very top of the gauge cluster assembly there is a bulb socket that those two wires connect to. The bulb is special GE558 and shines down on the heater control. Page 28 labeled A/C heater light.
Photo 3. The connector wires look like Orange and Pink/Black stripe. This connects to the Seatbelt/Headlight/Ignition Key Warning Buzzer unit and is plugged into a separate 4 wire white connector attached to the right side of the fuse panel. Page 18 circuit #40 and #80 Connector # C122
Click each page thumbnail photo to enlarge, might as well save them all your going to need them.
Link for the complete 1977 Corvette Electrical Troubleshooting Manual: http://www.europeancorvette.com/html...l_diagrams.htm
Last edited by bmotojoe; Nov 13, 2020 at 11:30 PM.
Photo 2. The cut wires look like Orange and a White.
The radio noise capacitor was factory installed using blue scotch locks connectors between Circuit #40 and Circuit #17 at the brake light switch connector.
Page 12 of the Troubleshooting Manual.
This is how the factory installed the radio noise capacitor between Circuit 40 & 17.
Photo 4. Not sure what area this photo was taken at?
I can tell you that the only factory installed Blue Scotch lock connectors I have found on a LATE 77 dash harness is of the photo above.
Also in Photo 3. The empty clear/white connector with the Pink wire looks to part of the cruise control harness.
Page 26 of the troubleshooting manual.
Good photo John 65!
Also, with the eyelets under the screws make sure when you tighten the screws that the wire eyelets are aligned with the bulb socket contact points. Meaning I think there is a little room for error with the diameter of the eyelet hole size.
I think the OP went AWOL.
77 Corvette - Dash wiring identification help needed
Hello. Thanks for the responses. Referring to the two wires with eyelets. Can someone tell me which of the center cluster bulbs these need to be attached to? When I took the center console out the wires were not connected to anything. Someone disconnected them for what reason I do not know. I’m attaching a picture. Thanks in advance.
I also see the top right copper tab on your printed circuit board has de-lamented from the backing.
Put a small drop of super glue on the backing and position it correctly.
Because the top one is a ground and the one below it is the temp sending signal your gauge may not read correctly if they are touching each other when the plug is installed.
Good photo John 65!
Also, with the eyelets under the screws make sure when you tighten the screws that the wire eyelets are aligned with the bulb socket contact points. Meaning I think there is a little room for error with the diameter of the eyelet hole size.
I think the OP went AWOL.
Thanks Joe
Here's 2 more, The contacts coming off that plastic bulb holder are what makes the connection to those 2 eyelets.
Thanks for the picture John. That helped a lot. So I looked at mine and someone removed the socket and bulb. That’s why I was so confused where the 2 wires went. Do happen to know where I could order replacement? Also thanks bmotojoe for your help.
If your interested in the correct 558 bulb I have a lifetime supply.
They are between $5.00 - $10.00 ea if you can find them
PM me your info and I can send it out to you in a few days no charge.
What makes them special is the magnifier glass dome at the end of the bulb.
Last edited by bmotojoe; Nov 26, 2020 at 11:26 AM.
77 Corvette - Dash wiring identification help needed
