I dont have any specifics for you, but I bet you have a bad ground somewhere.
Have you done any recent work on the vehicle prior to this happening?

 

Used multimeter and traced the path of power from the instrument cluster to the harness connector and found that 12v is not there when lights a turned on.

Sounds like you found the problem there?

 

What you are describing sounds like the taillight relay (front & rear side marker) and small light relay are not energizing.
I would start at the combination switch on the steering column and the ground G401

 

Thanks for the suggestions everyone. Will check ground and relays tomorrow morning and report back.

No recent work to the car, this just started happening one day. Forgot to mention that I did check the dimmer and it does dim the one light that works, so that's not it. Yes, I agree that no 12v on the wire at the instrument cluster is a problem, but need to figure out the cause of this....

 

Don't forget the combination switch as a potential problem.

 

Checked the following:
Combination switch - tests good based on the diagram provided and controls lights with the exception of what's described below.
Taillight relay - removed and re-seated resulting in front marker lights now working. Go figure.
Looked for G401 behind the glove box but was unable to pin it down in all the electronics back there. Will dig further as soon as possible.
Verified good ground on pin 12 of headlight combo switch.

Result: still no lights on the instrument cluster or heater controls. Red/blk wire on connectors at both these places get 12v power when the combo light switch is turned on. Red wire also gets 12v, but only when connected to the instrument cluster so I assume that this is the 'return' line of the illumination circuit. However, meter shows red wire is open relative to ground. Same result on the heater control connector. Oddly, there is one light in the cluster that comes on at the top right of the speedo and dimmer control works on this light - testing with multimeter finds that this one socket has a different ground than all the other lights..... No idea why.

I'm stumped.

 

Bulbs burned out?

 

I ran into a similar testing problem on the instrument cluster about a year ago when I was dealing with the equivalent circuit on a Honda element. here is a link to that thread, maybe it helps?

https://www.elementownersclub.com/threads/help-me-work-through-a-wire-diagram-dash-instrument-cluster-lights-out-confirmed-cracked-solder-joints.171290/#post-1766152

 

This is not sounding not good. The same taillight relay supplies 12 volts to both the small exterior lights ie side markers, and the dash lights. Starting to look like there may be a connection issue inside the fuse panel if you are not seeing 12vdc on the dash lights

 

Got it sorted out. After reseating the taillight relay, I thought to re-check for 12v on the red/blk wire on the blue connector to the instrument panel and got 12volts there. I spent an evening of quality time with the circuit board of the instrument cluster and a multimeter and discovered that the variable resistor for dimming the lights was shot - showed open no matter what the position of the dimmer was. Bypassed the dimmer and all the lights are now working. No dimmer, but I don't care.

Traylaw - thank you very much for the diagrams. These were VERY helpful and got me thinking in the right direction.

 

Got any pics of the instrument cluster circuit board or the bypass you did?

If it interests you, google “Honda instrument cluster repair” and you’ll find a bunch of small independent shops that repair gauge clusters. Alternately, you could pull a gauge cluster from a junkyard and those guys can often adjust the odometer to match your car.