New owner electrical bug sort out
Thread Starter
Instructor
Joined: Jan 2013
Posts: 167
Likes: 0
From: Battle Creek MI
New owner electrical bug sort out
Picked up a nice 1979 Yellow C3 last night. Didn't realize when I test drove it (during the day) that the lights for the speedo and tach are out as well as no power to the wipers.
Are these potentially related?
I have a shop manual and a laminated wiring diagram that came with the car. But haven't had enough time in the garage to look things closely. It was late last night when I got it in the garage and all I had time to do was give it a good cleaning. Today I had to work all day and it's too cold here in Michigan to mess with it again until the weekend.
Any thoughts?
Are these potentially related?
I have a shop manual and a laminated wiring diagram that came with the car. But haven't had enough time in the garage to look things closely. It was late last night when I got it in the garage and all I had time to do was give it a good cleaning. Today I had to work all day and it's too cold here in Michigan to mess with it again until the weekend.
Any thoughts?
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
IF you are not familiar/experienced with electrical/electronics, you are in a world of hurt, how ever some common sense can overcome some of that.....at expense of your body....you need look up/under the steering wheel column shaft and to the left side of the firewall, to find the fuse block, and get a good bright light on them to see if anyone is blown, due to age of the car, I suspect they all look good, but be advised they can melt internally from the corroded steel clips on the fuse block, and so the fuse LOOK good, but in fact is NOT....
so you need use a voltmeter to trouble shoot from there, it could be leading to a bad ignition switch on top of the steering column, or some other stuff also....
so you need use a voltmeter to trouble shoot from there, it could be leading to a bad ignition switch on top of the steering column, or some other stuff also....
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
The dash lights are on the same fuse as the tail lights, so you should check to see that they are working.
The wiper is not on the same circuit, but wiper problems are likely grounds, so ground the case and see if that works. You might check the cut off switch under the dash first.
The wiper is not on the same circuit, but wiper problems are likely grounds, so ground the case and see if that works. You might check the cut off switch under the dash first.
Instructor
Joined: Jan 2012
Posts: 215
Likes: 6
From: Mebane, NC
Firewall
Behind the fuse box is the firewall connector. Very poor design. Car worked on day would not start the next. Turned out to be a bad connection between the halves of the firewall connector. I've been advised to hard wire all the wires that go through the firewall. Looks like a PITA, will wait till I pull the dash later this spring. Also at least on my car, the dimmer in the light switch for the inst lights is CCW to make bright, opposite of most cars I've had.
Thread Starter
Instructor
Joined: Jan 2013
Posts: 167
Likes: 0
From: Battle Creek MI
I turned the dimmer both directions full sweep to no avail.
Here's a wrinkle: all the monitoring gauges back lighting work fine... (oil pressure, battery, etc). Are they on a different fuse by chance?
Here's a wrinkle: all the monitoring gauges back lighting work fine... (oil pressure, battery, etc). Are they on a different fuse by chance?
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Drifting
Joined: Jul 2005
Posts: 1,623
Likes: 29
From: The Netherlands
Speedo and tach lights could also be as simple as busted bulbs. You can relatively easy reach them from underneath the console. You can remove the screws holding the cluster in and pull it a bit forward to get some extra clearance. Removing the duct also helps a lot.
Besides the bulbs it's worth checking the plug going in the back of the cluster: some of the copper 'fingers' on the circuit board could be crooked. And finally it could be a matter of borken copper lines on the circuit board itself. Some carefull soldering could fix that.
After that back to fuses and grounds
Besides the bulbs it's worth checking the plug going in the back of the cluster: some of the copper 'fingers' on the circuit board could be crooked. And finally it could be a matter of borken copper lines on the circuit board itself. Some carefull soldering could fix that.
After that back to fuses and grounds