HVAC System Doesn’t Work With Remote Start, 2007 Toyota 4Runner, Viper 4806v

I bought a 2007 Toyota 4Runner last fall and installed a Viper 4806v remote start (I ripped the remote start out of the 3rd gen 4Runner I recently sold, and I had previously installed the remote start new in 2015). Once I got it properly installed I have not had any problems with it all last winter and no problems this winter until 2 days ago - right before this nasty cold snap we are currently having up here in central Canada. It was -30C last night (-22F) and that is certainly too cold to be working on a vehicle outside...

Anyways, the remote start still works, but as long as the remote start is engaged the fan does not blow and the HVAC console is not working, although it is illuminated and the clock is displayed. There are also a bunch of lights illuminated on the dash: air bag, brake, abs, 4-lo and center diff lock. Once I put the key in the vehicle and step on the brake to disengage the remote start, the lights turn off and everything goes back to working as expected. This problem is only seen when the vehicle is started with the remote start. If I start it with the key everything works normally.

Hopefully someone has a thought here cause I am scratching my head. It worked perfectly for over a year then all of a sudden breaks? I thought maybe it was the connection to the defogger output from the HVAC console, but I tried disconnecting that and it changed nothing...

I am open to suggestions

You need to meter the ignition and accessory wires at the ignition harness and see which one is not getting power during remote start and troubleshoot from there.

Probably blew a 30 Amp fuse on one of the Vipers 3 main ignition harness inputs. Red, Red/Black or Red/White. Check at the Viper connector.

IGN1 = Black/Red
IGN2 = Blue/Yellow
ACC   = White/Green
Start = Green/Black

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Soldering is fun!

Thanks for the replies! I dunno why, but I didn't get a notification that there were new replies...

Anyways, thank you! I will check the fuses, and failing that I will check the voltage on the ignition wires during start/run. This makes good sense, and I'm quite sure it'll be the issue. I'll post back after I've checked.

Any ideas why a fuse might have blown? I guess it just got real cold right when this happened. I guess extended cranking? Who knows...

It was the pink/white wire, ignition 2. It was a 20 amp fuse though... I guess this is an older harness or something.

Thanks for the advise, very much appreciated in this cold cold weather.

Come to think of it, the rear defroster hadn't seemed to be working after I noticed this problem. I bet something happened to the rear defrost circuit causing an over current on ign2 circuit? Possibilities... The remote start does turn on the defroster if the temp is low enough...

Again, thanks!