Defrost vents are clogged with mice debris can I

That is usually caused by a (blend door actuator) I think there are three of them on that A/C Heater plenum. You may be able to reach them without pulling the IP.

There is a flapper or trap door in the dash board that diverts air flow to various vents, defrost, floor, face, etc. If that stops working it will get stuck in the default position which is usually the defrost vents.

If you have a vacuum operated system you can check the vacuum hose for the system in the engine compartment for integrity. If that is ok then you have to get to the vacuum switch in the dashboard and probably replace it due to leaking vacuum - labor intensive and not cheap.

Any time the dashboard has to be removed you are in trouble money wise.

Taking the blower fan down would give you access to the heater. And mice can crawl through a hole as small as 3/4", check anywhere around your car for holes 3/4" or larger. They can climb on your tires and up in your engine too. Also check the vent between the hood and windshield.

i would say if you can axcess the blower fan. take it out and blow through the rest of the vents with compressed air starting with the one furthest away from the fan. you will need to have the key on and have someone constantly switching the vents to be used. cover your face. when you are all done, before you lock it up for the night spray a whole bottle a lysol to help sanitize your system and leave the windows cracked if weather permits. before you take it on a drive turn the system on for about a half hour on high so the smell isnt as strong as youre trying to warm up. happy holidays

they should come out but be carful not to damage the dashboard

Try grabbing one of those portable air tanks and a hose and blow gun. Set the control to floor only and start the car. blow with the compressed air into the defroster vents.It may get messy with leaves and the such but it aint no $800. It's worth a try keep charging the tank so you have a goo strong pressure coming from the nozzel. I didn't think it was necessary to tell you to put it on AC control during the project. Good Luck, Dana

First make sure it's not antifreeze which I doubt it is considering it only happens when it rains, it is probaly a clogged drain hose for the vent chamber which is located at the base of the windshied,or it is a clogged drain for the a/c evaporator box, if you can find a small drain hose or orafice under vehicle toward the base of the fire wall under vehicle you could feed a length of wire up through to unplug it, a mud wasp is the usual suspect planting a egg and packing it with mud to seal the deal.

Maybe your dashboard vents are clogged, obstructed or stuck in close position somehow.

If not, check the air hoses that carry the cooled air to the main vents are not clogged, bent, ripped or simply detached.
If its practical for you, check if they are correctly placed, clean and general conditions are ok if you can.

If above are not the issue, go to check outlets of the A/C unit, its filters for the possible reason.

u need to check the vacuum from the engine to the ac control head, the air defaults to the defrost when the system looses vacuum from the engine, this is for safety.

The drains in the wiper wells are probably clogged. You need to remove the plastic 'vent screen' under the wipers to clear out the debris. Remove the wipers and a few screws, not difficult at all. Also, under the hood, you will see a vertical tube on each side of the car under the wiper wells. These can be removed from under the hood without removing the wipers, but you will probably have to clear the wells anyway. What happens is the water backs up and enters the car through the fresh air inlet and comes in around the blower fan. Good Luck.