So. I just bought my first Acura a couple weeks ago after totaling my 8th gen Accord (so some Honda knowledge). It’s a 2006 TL and the most luxurious car i have EVER owned (lol). And of course... i wanted to upgrade stuff, prep for my shows next year.... yeah.

bare with me, please... I’ve been searching these forums for the last few days and found similar issues but nothing that has been posted to resolve it.

First thing i did was go after the factory radio. Swapped it out with a pioneer double din. Bought a special harness from MobileMax Audio and steering wheel control. Didn't splice ANY wires. Strictly plug and play in the most literal sense. Tested it out and i did everything right! Until i plugged in everything else (yes, the only thing plugged in was the double din), put everything back and tested everything out again.... just to find out that i messed up....

the defrost is on FULL BLAST. switching from hot to cold. BUT the display is illuminated, but no digital read out(picture included).





I have tried so many different things from checking all grounds and wires, fuses, disconnecting the battery and redoing everything in different orders... no avail. Pulled the blower fuse from under the hood to get it to stop. Finally went and pulled my resistor and it LOOKS okay; brand new, practically. Fan runs (obviously). And no melting or corrosion from the looks of it. So I’m stumped. Saw something about door regulators or something? But it didn’t look like they were related.

I’ll be going to AutoZone today and testing out another resistor and have the fuses and connections checked. I would LOVE to have this fixed sooner than later because i have a road trip coming up as well as use it for a DD with my kid. And it’s been hot, and about to get cold since it’s officially fall. 🙂

i appreciate you for reading and for any help.

 

Put oem radio back. If hvac works, then something is wrong with the custom harness.

Blower on max is a default behavior if display unit is not connected / no communication. Since radio connects to that display as well, I suspect the aftermarket wire harness. Also make sure that no pins are bent / push back in your connectors.

 

When I left my HVAC harness unplugged, it did that. It's separate from the radio but next to it. Either the plug, the HVAC unit or the resistor.

Easiest to start with would be resistor, then plug.

 

I guess i forgot to mention that one of the first things i tried was putting the oem stereo back in. No difference. Sorry for not including that.

and i tried a new resistor. Same thing. Nothing has made a difference. But did find out, however, the only buttons lighting up now are the ones in the picture.

 

All buttons are powered from the same source, so chances are that old filaments are broken after moving the buttons around. Replacing the bulbs should fix that problem. You might consider replacing them with LEDs - there are threads about that in this forum.

Check the fuses, especially the under-dash #7 and #30 (both should be 7.5A). Use test light to probe both sides of the fuses, with ignition key in ON. You can also test rest of the fuses.

Again, make sure that all pins in the plugs look fine. It's pretty common for pins to get pushed in as those aftermarket harnesses are not that great quality.

 

it’s not the bulbs that are the issue, it’s the whole head unit. And the first time i drove it at night is the first time i noticed those climate control buttons don’t light up or work. I’m assuming it’s another symptom.... because i don’t want to change those bulbs. 😂

i checked the aftermarket harness to make sure all the wires were good before i used it. So i guess next steps is the other wires. I know black is the ground on the climate control harness. But what other wires would be good to check? Fuses are all good. I double and tripped checked just because it seems like that would be the most likely thing. But guess not.

 

You wrote that some buttons don't light up. All the bulbs in the buttons are driven by two wires. They are all connected in parallel. If some don't light up; bulb is broken, it's not making a good connection, or circuit board is damaged. Fact that some buttons don't light up is not connected with climate displays not working.

If ALL fuses are good, then I won't list any more to check. In terms of checking if display has ground / powers, there is a ground, battery power, and key in acc/on power:


I can't find connector view for the display. You will need to go by the pin number and wire color.

If you have access to bi-directional scan tool, I would try to communicate with hvac control module. Either that or display is dead, assuming all power, ground, and communication circuits are fine.

Otherwise I don't have much more to write. I would still remove all aftermarket components, bring car back to stock, and then try to troubleshoot the displays.

 

did you unplug the battery while working there? those bulbs seem to be very temperamental and looking at them funny causes them to go out. You're saying you put back the old head unit and it didn't work either?


also how did you 'check the aftermarket harness" that "all the wires were good"? did you continuity test it with a multimeter?

 

Thanks, peter6. I’ll try to do that tonight. I’m thinking about putting it back together and starting from scratch. I have an option to take it to Acura or Honda to run a diagnostic before possibly purchasing a whole new head unit. But I’m trying to cover all the bases. At this point, I’m just so over it and willing to go back to stock and just put in a dang aux cord. 😭

I made sure the harness was good with a multimeter, yes. I also visually inspected it. All of them were putting out voltage. The only thing i could think of is something happened between then and now somehow. But i don’t think i “pulled too hard” or twisted anything.

I’m going to try going back in tonight and testing everything all over before i put it to factory. As well as making sure everything is grounded and such. I’m really not that good with all this electrical stuff, but i really am so grateful for all the help. Just over 48 hours before i leave for vacation to go into the mountains. Pray for me.

 

Maybe something got shorted when you were checking for voltage. I has happened to me a couple of times.