Yet another circuit board question....

[Mountaineerfan 44]

As I install the dash on my car, I need another set of eyes as I work on chasing electrical gremlins.

I replaced the printed circuit board and voltage regulator, as well as the light bulbs.  When I connect the harness to the dash, there are no lights.  Did I install the board correctly?  Is there anything glaring that I may not have done properly?

[Johns Summer of 69 14]

behind the plastic protectors, do you have the cardboard insulators? Are you using regular or LED bulbs? Have you replaced the headlight switch?

[Mountaineerfan 44]

1 minute ago, Johns Summer of 69 said:

behind the plastic protectors, do you have the cardboard insulators? Are you using regular or LED bulbs? Have you replaced the headlight switch?

Not sure about the cardboard insulators.  I'll check when I get home.  I've switched to LED bulbs, and the switch is new.

[Johns Summer of 69 14]

make sure they are there ;) I believe you might want to keep one bulb regular so you can dim the panel. Sometimes the regulator is defective. You might want to put the old one in to see it that is it?

[Mountaineerfan 44]

Do the insulators go under the board, or between the board and the nut?  What do they look like?

 

[Midlife 814]

Insulators go first on the metal, then the circuit card, then the nuts.  Be careful to ensure that the posts do not touch the metal case; this is hard to detect unless you're using a multimeter. 

As for no lamps, bad ground (I can't see the bolt underneath the flap in this picture), bad contacts, bad wiring, bad fuse, old age and age-related macular degeneration; paper bag over your head. 

[aslanefe 333]

Are the polarity of LED lights correct?

[ralt962 11]

Agree with Midlife (he is the expert here).  Check the grounds.  But also check the blue lens for each light.  I used the dimable LEDs which are great, but I found that all the lenses were melted from the original bulbs.  This made the cluster look like no lights at all.  Once I changed to new blue lenses and the dimable LEDs I'm all set.  They do dim correctly and have the original look in the car.  

Plus thanks to Midlife, I have all my gauges working correctly.

[Mountaineerfan 44]

Insulators are there, so that’s good! I’m still chasing the gremlins. Fuses are good, switch is new, voltage regulator is new, board is new. Thanks for all the advice! I’ll keep asking questions as I eliminate problems!

[Mountaineerfan 44]

On 8/8/2018 at 2:22 PM, Midlife said:

Insulators go first on the metal, then the circuit card, then the nuts.  Be careful to ensure that the posts do not touch the metal case; this is hard to detect unless you're using a multimeter. 

As for no lamps, bad ground (I can't see the bolt underneath the flap in this picture), bad contacts, bad wiring, bad fuse, old age and age-related macular degeneration; paper bag over your head. 

Are you talking about the bolt holding the regulator on? There is no cardboard there between the board and the chassis. Should there be?

None of the gauges are working  

What readings should I get when using the multimeter. Sorry if I sound foolish, I really thought the board swap/LED install would be easy....

Unfortunately I cannot get my interior reinstalled until the cluster works!

[Midlife 814]

Yes, the bolt holding the regulator on; the pad beneath the bolt should touch the grounding plane of the circuit card.

 Put your multimeter on resistance, one probe on a gauge post, the other on the metal chassis of the dash cluster.  You should see 100's of kilo-ohms or more.  If you see 14 or 0 ohms, one of the posts is touching the case.  If the post you are testing is a CVR output post, then any of the three gauge posts for that signal can be touching the metal housing.  The ammeter posts are not related to the CVR and it is absolutely essential that they do not touch the metal housing. 

[Mountaineerfan 44]

Should there be a cardboard insulator under the light bulbs?

[Mountaineerfan 44]

I took it apart. As I replaced nuts on gauges, I tested each post with a wire on the chassis, and a wire on the post. Never moved the needle. As I placed each bulb, I would recheck the posts. Nothing. I bolt the car on. Still no reading. I snap the board to the CVR, and all of a sudden I get readings of about 4.15 on each post. I’ve included some pics. The CVR bolts directly to the chassis with the circuit board under it. 

Thanks again for any help!

[Mountaineerfan 44]

Success!

-ish. 

Gauges are working, high beam lamp comes on, and parking brake light comes on. Still no dash lights or turn signals. I put in LEDs, but what are the chances I have ALL of them installed backwards?

[Midlife 814]

No insulation pads under lamps. 

With headlight knob pulled out, probe the disconnected dash cluster plug for pin 11 (blue/red wire) for voltage.  You may have a bad fuse or broken wire to the dash cluster.  You did remove the paper sack over your head, right?  *G*

If you think the LED's are polarity sensitive, simply take one of the turn signal bulbs and rotate it 180* and see what happens. 

[aslanefe 333]

Did you check the voltage on the pads that the dash light bulbs contact?

[Mountaineerfan 44]

On 8/12/2018 at 9:23 AM, aslanefe said:

Did you check the voltage on the pads that the dash light bulbs contact?

Interestingly, I get no continuity across any of the bulbs when I test (see pic). Even on the two that are confirmed to be working. I removed the headlight switch, and had continuity from the switch to the circuit board, so the fuse and wiring seem good in the dash. I was unable to get continuity in the switch itself for instrument lights, but everything else seemed good, so I’ll try a new switch. I tried turn signal, and still no lights. I turned the light sockets 180 def and still no light. I’m getting frustrated, but hopefully the new switch will help!

[Midlife 814]

Put an incandescent bulb instead of an LED bulb and see what your meter reads.  You should also set the dial to 200 not 20k.  LED's have unusual resistance properties and require a certain amount of voltage/current to register a low impedance. 

[aslanefe 333]

Take all the LEDs out and measure the "voltage" not resistance on the pads with headlights on and switch turned to make the lights bright (you can turn off or brighten the cluster lights by turning the switch). Make sure you are getting power to the pads. If there is power to the pads, the problem is either the bulb carrier (the black pieces) contacts are not touching the pads (bend them a little to make contact), or LEDs are bad or reverse polarity.

[danno 128]

I hate to state the obvious, but you MUST have a connection between the metal chassis that the whole thing is mounted on and the chassis of the car.  There is no ground connection in the wire connection that plugs into the flex assembly that has 14 wires.  It would have cost Ford an extra 5 flippin cents, so they are relying on the screws to make the connection.  When you are probing around and testing with it in these photos, you must have a ground wire connecting the metal to ground. 

I am guessing you are, but if you are not, that could explain it. 

[danno 128]

By the way, LEDs have a definate polarity. It would be odd that all of them would be backwards, so the next thing is that there is no voltage to them.  Do what Randy said, check for voltage on the headlight switch. 

[Midlife 814]

15 minutes ago, danno said:

I hate to state the obvious, but you MUST have a connection between the metal chassis that the whole thing is mounted on and the chassis of the car.  There is no ground connection in the wire connection that plugs into the flex assembly that has 14 wires.  It would have cost Ford an extra 5 flippin cents, so they are relying on the screws to make the connection.  When you are probing around and testing with it in these photos, you must have a ground wire connecting the metal to ground. 

I am guessing you are, but if you are not, that could explain it. 

That is absolutely false.  All 69 and 70 dash cluster connectors, whether for standard or tach dash, have ground wires.  Pins 4 for tach dash, 8 for standard dash.  There is a trace for the ground plane for the bolt that holds the CVR that goes to the dash cluster flap.

[danno 128]

13 hours ago, Midlife said:

That is absolutely false.  All 69 and 70 dash cluster connectors, whether for standard or tach dash, have ground wires.  Pins 4 for tach dash, 8 for standard dash.  There is a trace for the ground plane for the bolt that holds the CVR that goes to the dash cluster flap.

I stand corrected. You are correct again, almighty one.  There is a ground wire, but perhaps it has been disconnected or broken off?  I think it goes to a screw lug by the door?    If the high beam lamp turns on like it should, then you are getting a ground and my idea does not matter.  

Turn on the headlights, rotate the light switch all the way CCw until it clicks, and then check the voltage on the blue wire with the red stripe on it. 

[Mountaineerfan 44]

So I bought a new headlamp switch and that fixed the dash light problems.  Still no turn signal lights, but I think that may be an issue with the flasher relay.

Thanks for everyone's help!  I'm excited to get the interior back together.  I'll keep you all informed!

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