1994 Gmc K1500 removed dash, now there is high idl

My evaporator core went bad on my 1994 gmc suburban. 🙁 Of course this appears to be one of those jobs where you go in to fix the problem and you end up with two – five other problems that where not there before you started. I cannot live without a/c so yesterday I started tearing the dash down. I removed the entire dash from the vehicle including the speedometer cluster, HVAC controls, radio ect basically everything that has to be removed to get the dash out.

There is a large ground wire and a smaller ground wire which got grounded to the bottom of the dash. I also removed them. Beside the ECM to the left was a white box which was clipped onto wire harness sheath which housed wire thats go to the ECM.

Unfortunately the job was taking longer than expected and I had to have a way to get to work, so I had to get it at least drivable so I could make it to work the next day. I put the steering column back up and put the steering wheel on. I reconnected the head light switch, the dimmer switch and the interior dome light of or auto on switch.

Forgetting about those grounds and that white box beside the ECM which I though was possible just an audio amplifier I took the truck out for a spin. Well I went to anyways. As soon as I turned on the headlights I noticed that only the passenger side headlight was working unless I had the high beams on. Then I remembered the ground under the dash. I hooked up the large ground and the headlights returned to working like normal. As I drove the truck I noticed it wasn’t shifting out of first so i pulled it back in to check the problem. I reinstalled the white box which I thought was an audio amplifier and the truck now shifted as normal.

My only two problems now is that when you come to a stop, the truck idles higher, possibly around 2-3K. Last night when I came home from my test drive, as soon as I turned the headlights off, the idle dropped down to normal. Today on my way to work, it was idling higher than usual again and this time turning the headlights on and off, seems to have no affect on the idle.

Also only when I have my headlights on, the passenger side turn signal blinks normal for a second or two and than starts blinking fast, like a bulbs out but none are out. If I have the headlights off, it blinks normal.

Neither of these issues where prevalent until I took the dash out. Would not having the instrument cluster in, or HVAC controls cause this? I don’t see anything that is not grounded under the dash anymore. I temporarily grounded everything to the metal on the steering columnn until I put everything back together. Basically I am driving the truck with no dash, speedo cluster, radio, HVAC controls but everything else is there. Not sure where to start, please help.