I just picked up a 99 accord 4 banger yesterday, the commute to work in the truck was killing me. The truck chugs gas like a frat boy chugs beer. The car has a couple issues, the one I currently need help with is the lights for the heat/ac blower buttons. The lights above the buttons work that show which area is selected but the buttons themselves are not lighting up. I have checked the fuses in the cab of the car both on the driver's side and on the passenger's and didn't find any that were blown. What else it there left to check? Here is a picture of what is going on, any help would be appreciated. I am working on addressing the irregular idle issue with info on other posts that I found, this forum is a great resource.

 

Just so I'm correct, everything with the HVAC is working - blower blows, temp ****, vent changes,ect. Just when the headlights are on the "back lighting" of the buttons is not working? Correct?

 

That is correct, everything except the backlighting works.

 

Are you ok with pulling the HVAC contol unit? Pins #10 and #22 are what I'm wanting to check....with the headlights on #10 should be hot and #22 would be the ground....more to this story but that is the short version.

 

I'll check tonight. I don't have a wiring diagram, I'll assume the top left pin is #1 and they ascend left to right. If I'm wrong let me know.

 

Sorry, that bit of info would have been important...yes "tab" up and looking at the wire side......see if these help with where I was trying to go,

 

11.6 volts on #10 with the headlights on and 22 has no voltage but since its a ground that makes sense. It does have a good connection too, I put one probe of the multimeter into 10 and the other into 22 and it completed the circuit and gave me 11.6 volts.

 

So this is sounding like something inside the unit.....when the headlights are on, the voltage is there.

I'll do some digging into other ideas, you might do the same, I'll let you know what I find....please do the same if you find anything.

 

Don't spend too much time on it, it's not a huge deal the car still runs. I might try and take apart the unit this weekend when I have some time to really dedicate to it. Tonight I had to free up the tie rods that the local garage said were seized and they couldn't fix my alignment. Took me 15 minutes to free them up because I had to dig out my jack and jack stands. I might need to find a garage where the techs aren't so lazy.

 

Looks like you need to check the bulb.....I couldn't remember if this had LED's inside the button or one backlight bulb.....then I really looked....sorry...at the pic and I see when the button is pushed it does light up.

See these for where I'm going. First pic, #1 is the bulbs for the back light....the other two have red arrows (my paint skills suck) to where the one I think needs replacing.......again, I read this wrong so sorry for the run around.