Greg5OH

Well, i thought new caps in the ecu solved my auto climate control issues but no. Heres whats happeneing.

Few weeks ago everything was working fine. Put it on auto X temp and it maintained it.
Recently-u put it on any temp and it starts blasting the fan and boiling you. Even if you turn the fan down and temp down its still hot air-like the blend door is stuck to hot?
another day the auto didnt blast the fan but it was still hot air even when i told it to do only 18 degrees.

main problem: car only blasts hot air.

Where can i start with this?

LScowboyLS

it could a be a blend door or heater control valve issue, there is a common cable that becomes unhooked on LS400, search on it here on Club Lexus - there was a post on this within the last month, for example

also, you could have an issue with the A/C system proper, although A/C issues such as leaks, compressor, etc. are very rare on LS400 in the first 300K miles or so, but these cars are starting to get to be 20 years old, and rubber hoses eventually leak, and seals eventually go bad

feel of the suction line coming off the compressor while car is at about 1500 rpm with A/C on and see if it is cold - and be careful of the fan and belts, don't lose a hand!

Greg5OH

AC aside, it should let in cold air from the outside with ac off, or at least not max hot. I shall try finding this thread about unhooked cables but i foudn the search function is terrible and can never find what i need.

Greg5OH

https://www.clublexus.com/forums/ls4...-cold-air.html

goign to check into these items here
Will look into the room temp sensor resistance values first, then check out blend door actuation.

LScowboyLS

here is an easy test, there is a set of pliers you can buy on any tool truck, and they are for clamping a coolant hose completely flat so that there is no flow, without hurting the hose.

you take those pliers and clamp off the heater hose containing the heater control valve, and that is like forcing it closed, and if that makes a difference, then either the heater control valve or the cable going to it or the logic controlling it is faulty.

Greg5OH

doubt its the programming...worked fine before..probably mechanical or the interior sensor died.

LScowboyLS

I think it is likely that cable that becomes disconnected, I have seen many threads here on Club Lexus detailing this.

Greg5OH

i havetn found anything about which wire becomes disconnected. Do you happen to knwo the colors of them? Is it routed behind the center console cover/radio?

sha4000

iTrader: (1)

Is this the thread???
https://www.clublexus.com/forums/ls4...nctioning.html

LScowboyLS

yes, that's one of them

it's a cable issue, not an electrical wire

Greg5OH

interesting. so it seems like ther eis some sort of white glue that holts the cable to the body and it becomes disconnected there? Is that located behind the glove box?

LScowboyLS

I would continue searching for threads on this, there may be more than one different cable that is known to be prone to become disconnected

Greg5OH

AHA! i think i foudn the problem. WHen i took apart the lower dash a while ago, which i just did now as well to test the resistor, i notice i didnt actually plug th eelctrical connector back in, only the hose! DOH!
im sure everyhting will work fine once its plugged in. Worked fine before, then "mysteriously" stopped working when i messed around with some stuff.

sha4000

iTrader: (1)

We all have been there!