Only max cold or max heat - 2007 (1 Viewer)

[scottw]

2007 100, AC blows cold when set on max cold, but as soon as I go up one step, to 65 degrees, it blows max heat, no matter what the temp says. Very strange, since both AC and heat are working well, but all full on heat except when set at max cold. Have a decent local shop but they are not Toyota experts, let alone LC. They said they think it might need part 87106-60200, a server assembly, but they sound like they don't really know and are just guessing/hoping that's the issue.

200K, was stored for two years, not sure if that is a factor. Everything else works well (hope that doesn't jinx me).

Did some searching on Mud but couldn't find anything that sounded similar. Thanks for any ideas.

 

[trdcorolla]

I think I remember people cleaning the intake sensor, I think it's little cutouts under/by the ignition key. Maybe yours is full of lint/dirt or the tube behind it might be disconnected/fallen out.

 

[YezusLX]

You mentioned this rig was stored for a couple of years above. Was it on a battery tender or battery removed? Or was it driven occasionally while you were away? The servo could resolve it. May take a stab at checking out the techstream thread and get some more solid answers. IF it's a servo, techstream should see it almost immediately as an issue because it likely won't respond to its status check. If you recently replaced the battery or it was on a tender it could cause the servo or other electronics for lack of a better term "freeze" in place requiring a reset. This also can be done via techstream. Just my own W.A.G. but maybe this will give you some direction before dropping money on parts and labor.

 

[scottw]

Thanks, it was on a battery tender, I think started occasionally but not driven.

 

[YezusLX]

I would start with the techstream journey. This will save you money on diagnostics and pay for itself in the first two minutes. Low, inconsistent, irregular voltage makes vehicles behave erratically sometimes. Try this out:

How-To: TechStream In 5 Minutes

Getting Techstream up and running can be a bit of a pain. Hopefully this helps someone get started quickly. Step 1: Purchase an OBD-II / Mini-VCI interface. - I have sold out of my cables and supply chains are back in order, so no reason to purchase more. Anything like this will work: Mini-VCI...

forum.ih8mud.com

 

[TJS8040]

I recently had same problem and it was the interior temp sensor.

HVAC Troubleshooting

Mudders, I've had a few ask, so I think it warrants its own post - I assume more might have had/have this issue. Maybe this could end up in the FAQ, if enough people post solutions to HVAC problems (with pictures!). PROBLEM: Temperature control for HVAC does not work. Cold is cold, 65 and...

forum.ih8mud.com

 

[plaidwagon]

I’ve been learning more than I want to after changing a leaking heater core and now servo issues trying to get my heat to work. There’s two servos just above the transmission tunnel. Driver side is for vent selection and passenger side is the air mixer. Try turning the knobs and watching them cycle to make sure the range of motion is correct. Sounds like the temp sensor thing might be your issue but verifying your servos work correctly rules out a couple variables.

 

[Rix 45]

I recently had same problem and it was the interior temp sensor.

HVAC Troubleshooting

Mudders, I've had a few ask, so I think it warrants its own post - I assume more might have had/have this issue. Maybe this could end up in the FAQ, if enough people post solutions to HVAC problems (with pictures!). PROBLEM: Temperature control for HVAC does not work. Cold is cold, 65 and...

forum.ih8mud.com

I had the same problem with a "99 LX 470. Opened the plastic from the key as described here and what do ya know ? The tube and wire were both not connected. Connected and buttoned back up and all is well.

Thank you all,
Eric.

 

[scottw]

To follow up on this, finally found time to deal with it and based on @TJS8040 and @Rix 45 posts opened up the panel where the temp sensor is and the black wire was disconnected. Didn't have any MAF cleaner on hand, so just reconnected it without cleaning the actual sensor and works perfectly now. Thanks all!