Lost the lighting on my dash

-
Kikowillers

Kikowillers

Well-Known Member
Joined
Aug 12, 2012
Messages
91
Reaction score
3
Location
Eaton, Australia
Hi folks!

Today I lost the lights on half my rallye dash - not the blinkers, high beam, etc, just the background illumination.

I took the dash out of the car and found that the two bulbs which are not working take power from the same wire/pin. (Please see picture attached)

I then had a look at the conector which plugs into the 3 pins on the back of the dash - this is what I found (see picture).

1 - Pink wire has continuity to ground (blinkers)
2 - Brown wire does not have continuity (maybe the problem?)
3 - Blue wire has continuity to ground (high beam)

I'm not an electrician and to be honest, pretty ignorant about electrics, but it looks to me that the brown wire is at fault somewhere.

So the questions are:

a) Am I going about this the right way?
b) Where does the brown wire come from? In case I need to check for faults...

Cheers!
 

Attachments

  • securedownload.jpg
    132.2 KB · Views: 284
  • securedownload-1.jpg
    165.1 KB · Views: 288
OK , you have 2 seperate boards with 2 illumination bulbs each. Both need the same power supply so there is a wire for each board. I think you have figured out that much.
The power comes from first the headlight switch. Then a fuse marked "park'.
Other lamps such as shift indicator, radio dial, get the same power supply.
So what works and what dont ? If those others dont work the problem probably isn't in the dash itself.
Keep in mind that none of the dash lamps will work while the panel is dangling from the harness connectors. Like most everything else on the car, It needs a chassis ground.
You can attach a temproray ground wire for testing. A perminate ground wire is recommended.
 
Wait ! Ignore most of my previous post. The pic looks as if the harness connector wires are routed through the wiper linkage.
There are several small things that just dont look right to me.
I think it best that I back away from this one. Good luck though.
 
Thanks Redfish

The only lights at fault are the ones marked on the image of the circuit. All other lights work, that's what got me puzzled.

So if some of the lights work, it's not the switch nor the portion of the wire before it splits for the two circuits. Is this correct?

I'm wondering if it could be just a bad connector?

Cheers.
 
RedFish said:
Wait ! Ignore most of my previous post. The pic looks as if the harness connector wires are routed through the wiper linkage.
There are several small things that just dont look right to me.
I think it best that I back away from this one. Good luck though.
Click to expand...

The harness does not go through the wiper linkage, it's just a bad picture... Hehehe

What else looks incorrect? It's all original wiring...
 
Clean the contact areas on the power side and the ground side on the board with fine sand paper,
and wipe with methyl hydrade (rubbing alcohol).
Test wires with test light to see if power there.
See if this is the problem first then go from there.
Hope this works. Also could be the ground side of the board not making
contact.
Darryl
 
The issue that keeps coming to mind is the continuity.

After unplugging the harness connector I used a multimeter and could not get continuity from the brown wire to ground, but the other pink and blu wires did.

Does that mean there's a fault in the brown wire?

Cheers!
 
The steel pins on the back of the circuit board which are "swaged" onto the board, the pins that the connector plugs onto, are known to become loose where they join the circuit board. There is one such pin on the board in the picture, between the two suspect lights joining the copper circuit. My guess is that it is loose. The easy solution - is a dab of solder where the pins join the copper circuit, to ensure continuity, or a wire soldered directly to the copper circuit and spliced into the harness on the other side of the push on connector.

Good luck
 
Do all the back ground lights not work? Wiggle the light switch while the
meter is connected, could be the light switch itself .
Yes there should be power there when you pull the light switch.
I am a little confused my self, just trying to help.
Darryl
 
The lights on one side of the dash work (instrument lights), which should prove the headlight switch itself is good. Yes, the headlight switch dimmer mechanism is probably the primary source of dash light problems if all the dash instrument lights quit.
 
monook said:
x2
Click to expand...

Thanks guys. I'm from Eaton, Western Australia.

I thought it could be the circuit pin too, but there's no continuity on the wire when it's NOT connected to the pin, so it looks like the wire may be the problem. And yes, all the other lights work.

Do you guys have any idea where the positive wire from the headlight switch gets split into two wires for the two circuits?

Cheers!
 
No continuity to what? When disconnected that pin should be continuous to the corresponding pin on the other (round) connector, and to the headlight switch where the instrument light feed comes from.
 
I would check for power there - turn on the headlights and you should have power at that pin in the connector - bear in mind it will vary any where from 0 to 12 volts depending on how the headlight dimmer is set.
 
d55dave said:
No continuity to what? When disconnected that pin should be continuous to the corresponding pin on the other (round) connector, and to the headlight switch where the instrument light feed comes from.
Click to expand...

I checked the wire, not the pin, for continuity to ground. Got nothing.

The other two wires from the harness connector (that you can see in the picture) have continuity to ground - both checked on the wire disconnected from the pins. They feed the left blinker and the high beam dash light.

Am I checking the wrong thing here?? Electrics is definitely my downfall...
 
Yes, you are checking the wrong thing here, check for voltage at that wire with the headlights on, and the voltage should vary as you turn the dimmer switch, The other wires show continuity because they are grounding through other things in their circuits....light bulbs, sending units etc.
Another check - with your meter set on continuity, connect it to the suspect pin on the circuit board, and where one of the bulbs plug in, wiggle the pin and watch the meter.....
 
One other thing....if you connect the battery and have power on with the dash removed BE SURE to insulate the large red wire that feeds the ammeter as it will be live. In fact,I think that you may have to hook the two ammeter wires together, or re connect them to the back of the dash in order to power up the system and troubleshoot the lighting issue.
 
Thanks for the help so far Dave.

The instrument cluster is in the car and the only thing not connected is the harness connector with the 3 wires we're talking about. Eveything else is where it's supposed to be.

Can I reconnect the battery and test for voltage with the dash like this? Even with no ground (the instrument cluster is not bolted to the car)?

Cheers!
 
Yes, just be careful that the ammeter studs and connectors don't contact anything and make a ground, you will blow the fusible link. It wouldn't hurt to install a temporary ground wire either, but to just check voltage at the suspect wire, no problem. Try hooking the connector back up and wiggling it, and the surrounding harness with power and the lights on to see if you can get the lights to flash on and off. You have checked the bulbs with a meter right? Sometimes they don't seat properly in the plastic holders and stop working, or go intermittent,
 
Temporary ground - perhaps from one of those screws that hold the center clock or tach in your dash - in you pic it looks to me like good place, and run it to any good chassis ground, or right to the battery negative terminal.

I am headed down under on sunday, back to work in PNG via Brisbane! Of course no where near your neck of the woods in Western Aus.

Good luck.
 
I'll probably write a short novel here. Too many of those who should read it never will. :(
I'll start with I'm sorry about my first post in this thread yesterday. At that time I was on Skype working with another rallye panel owner. He and I were both looking at this thread at that same time. I didn't properly read your first post. Too many things going through my mind at once.
What's wrong with the pictures... To pull this panel out a bit really is waisted effort a dangerous too. Its somewhat typical though so please dont take any of my comments personally.
I'm going to guess the very first thing you did was move what was a known working bulb/socket to a fault location, supplyed power and it didnt work. That suggests the power supply is the problem. Fact is when you pulled the panel you lost the ground path. So no lights would work, new or used, in any location.
If you had seen as many broken contact pins as I have you wouldn't have pulled that harness connector off at an angle. The only safe way to remove the connectors is straight away. I use a plastic tool between the connector and the board to pry in different locations around the connectors.
1970 model is 42 years old. Every part of the instrument panel is 42 years old. You might continue on your current path and get those 2 lamps working today and have another lamp fail tomorrow. Maybe you can replace the 8 bulbs one or 2 at a time in this manner without breaking something. I'll bet against that.
If you want to fix it, start by properly removing the panel. Detailed instructions are in the factory service manual. Take the panel to the workbench for service. Clean, inspect, test every contact point. Install 8 new bulbs. Apply small amounts of di-electric silicone at the contacts during reassemble. Done right it might be good for another 42 years.
Forget the temporary ground wire. Install a permanent dedicated ground wire from the lower screw at the center gauge pod to the phillips oval head screw that holds the fuse box in place. Put a male/female spade disconnect in this wire so it never has to be removed at those end terminals for service.
One more thing.. The one bulb socket I can see in your pic appears to be what was phased out in 1967 ( May not apply to export builds ). I think they should be to smaller sockets for bayonette type bulbs such as #158, #194, or Sylvainia #2825.
Happy moparing
 
RedFish said:
I'll probably write a short novel here. Too many of those who should read it never will. :(
I'll start with I'm sorry about my first post in this thread yesterday. At that time I was on Skype working with another rallye panel owner. He and I were both looking at this thread at that same time. I didn't properly read your first post. Too many things going through my mind at once.
What's wrong with the pictures... To pull this panel out a bit really is waisted effort a dangerous too. Its somewhat typical though so please dont take any of my comments personally.
I'm going to guess the very first thing you did was move what was a known working bulb/socket to a fault location, supplyed power and it didnt work. That suggests the power supply is the problem. Fact is when you pulled the panel you lost the ground path. So no lights would work, new or used, in any location.
If you had seen as many broken contact pins as I have you wouldn't have pulled that harness connector off at an angle. The only safe way to remove the connectors is straight away. I use a plastic tool between the connector and the board to pry in different locations around the connectors.
1970 model is 42 years old. Every part of the instrument panel is 42 years old. You might continue on your current path and get those 2 lamps working today and have another lamp fail tomorrow. Maybe you can replace the 8 bulbs one or 2 at a time in this manner without breaking something. I'll bet against that.
If you want to fix it, start by properly removing the panel. Detailed instructions are in the factory service manual. Take the panel to the workbench for service. Clean, inspect, test every contact point. Install 8 new bulbs. Apply small amounts of di-electric silicone at the contacts during reassemble. Done right it might be good for another 42 years.
Forget the temporary ground wire. Install a permanent dedicated ground wire from the lower screw at the center gauge pod to the phillips oval head screw that holds the fuse box in place. Put a male/female spade disconnect in this wire so it never has to be removed at those end terminals for service.
One more thing.. The one bulb socket I can see in your pic appears to be what was phased out in 1967 ( May not apply to export builds ). I think they should be to smaller sockets for bayonette type bulbs such as #158, #194, or Sylvainia #2825.
Happy moparing
Click to expand...


Have to say I totally agree with redfish, his points are all very good. Definitely change all bulbs while it is apart.
 
Kikowillers
Just trying to help before I go to work. You say half the dash lights up?
And there is no power to the brown and yellow trace wire?
Yes I agree with Redfish on checking and cleaning everything on these
old cars as I will have to do the same.
What about the other half of the dash, can you take a picture?
What wire is lighting that up?
Me check post when I get home and hope you find the problem.
Darryl
 
You must log in or register to reply here.
-

Back
Top