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Posted

The car blows only cold air. Becasue I live in Dallas, spring is around the corner, and so is the warmth. So my question is what can I do as a quick fix (reasonable) to get heat. What can I ask a shop to do/check with out breaking the bank. Anything short of replacing the heater control valve. Sorry, 1993 sc300 120,000k.


Posted

Same happened to mine a year ago. The problem was the solenoid valve that opens/closes the heater valve. It is a small black plastic part close to the firewall on the passenger side engine compartment. It has 2 small 1/4" vacuum lines going to it and an electrical conector. If you unplug it and check with an ohmeter between the terminals you should read about 15 ohms I think. Mine was open circuit so it was dead. A new one cost $138. Its worth about $3 but there you go. Lexus dealers say it is fairly common to fail. Good luck

Posted

I agree with Bess, however, when you find the valve, just swap the 2 vacuum lines and voila, heat. However, do not forget to swap them again in the summer...............

  • Like 1
Posted

I agree with Bess, however, when you find the valve, just swap the 2 vacuum lines and voila, heat. However, do not forget to swap them again in the summer...............

I think I located the part in question. Is it about the size of a lighter with two hoses leading in to the bottom, and the electrical connection on top? If so, swapping the lines wont' do any damage?

Posted

I agree with Bess, however, when you find the valve, just swap the 2 vacuum lines and voila, heat. However, do not forget to swap them again in the summer...............

I think I located the part in question. Is it about the size of a lighter with two hoses leading in to the bottom, and the electrical connection on top? If so, swapping the lines wont' do any damage?

Topped up coolant level, nothing. Swapped hoses, nothing. Still looking for options.

Posted

I agree with Bess, however, when you find the valve, just swap the 2 vacuum lines and voila, heat. However, do not forget to swap them again in the summer...............

I think I located the part in question. Is it about the size of a lighter with two hoses leading in to the bottom, and the electrical connection on top? If so, swapping the lines wont' do any damage?

Topped up coolant level, nothing. Swapped hoses, nothing. Still looking for options.

Yes, that sounds like the part. Swapping the 2 vacuum lines(hoses) won't work. You need to disconnect the electrical connecter and put an ohmeter across the solenoid terminals. If it is open(high ohms) as I suspect, then the solenoid is shot and needs replacing. As a temporary fix and to check the valve and heater core you could plug the two vacuum hoses together somehow and that should open the valve and allow hot water into the heater core.

Posted

It is nice to meet a "GOD" sometimes!! You hit the nail on the head. I joined the two lines together and had instant heat. When it is 29 degrees out side that is a beautiful thing. On to the next question. What does this mean now? Can the car run with this configuration with out any problems? What needs to be replaced and where can the part in question be found and for how much?

Posted

My heat blows cold too. I tried swapping those two vacuum lines, but nothing changed. I think the valve might be bad, but I don't have a multimeter handy to test it at this time. They said the heater core is 16 hours labor to change out because they have to remove the entire engine to get at it. Is that true?

Also, as soon as I press the front defrost button, the A/C lights up, and the vents open up to outside air. That makes absolutely no sense to me. Is that normal, or is my climate control just FUBAR?

Oh, and I just read the last 2 posts now, I will go get a hose joiner and try that method. Thanks.

Posted

I heard from a friend of mine that he took out his "heater core" pressure washed it and it fixed his problem, i had a few cars in the past that had very low to no heat but i never kept them long enough to have it checked out or time to fix it myself, but i guess that could be something to look into. Hope this helps.

Posted

Yes, that sounds like the part. Swapping the 2 vacuum lines(hoses) won't work. You need to disconnect the electrical connecter and put an ohmeter across the solenoid terminals. If it is open(high ohms) as I suspect, then the solenoid is shot and needs replacing. As a temporary fix and to check the valve and heater core you could plug the two vacuum hoses together somehow and that should open the valve and allow hot water into the heater core.

Hey thanks again! I spliced the two vacuum lines together with electrical tape and a heat gun. INSTANT HEAT! Awesome. So I guess my heater core and climate control are fine. I still think its retarded that the A/C comes on when I hit the front defrost button, but oh well, nothing's perfect. Thanks again bess! :D

Posted

It is nice to meet a "GOD" sometimes!! You hit the nail on the head. I joined the two lines together and had instant heat. When it is 29 degrees out side that is a beautiful thing. On to the next question. What does this mean now? Can the car run with this configuration with out any problems? What needs to be replaced and where can the part in question be found and for how much?

I ran mine "bypassed" for about 8 months but just recently bought a new solenoid. I tried to find the part # but unfortunately I can't find it. Anyhow, I got mine online from http://www.lexuspartsmall.com/ . It was about $138 and if you e-mail them say you need the solenoid that opens/closes the heater valve and they will give you the part #. It is quite a common part to fail. Hence the exorbitant price. Here in Canada the dealer wants $270 for the part. I checked some wreckers yards on the internet but most want $75-100 for it used so I thought I should go new. Good luck.

Posted

... I still think its retarded that the A/C comes on when I hit the front defrost button, but oh well, nothing's perfect. Thanks again bess! :D

The A/C comes on to dry out the air, and the outside air is used so that you can push the moisture out of the car.

Personally, I immediately switch it to recirculate so it dries out even faster.

Posted

i have the heater valve from a parts car if anyone needs. 55 shipped

If somebody can get me a pic of the valve, I'll post a part number for it.

  • 2 months later...
Posted

Spring is here, I unjoined the two vacum lines, but no cold air. Do I need to do something once the lines are unjoined & back in their original configuration? Thanks in advance.

Posted

My heat blows cold too. I tried swapping those two vacuum lines, but nothing changed. I think the valve might be bad, but I don't have a multimeter handy to test it at this time. They said the heater core is 16 hours labor to change out because they have to remove the entire engine to get at it. Is that true?

Also, as soon as I press the front defrost button, the A/C lights up, and the vents open up to outside air. That makes absolutely no sense to me. Is that normal, or is my climate control just FUBAR?

Oh, and I just read the last 2 posts now, I will go get a hose joiner and try that method. Thanks.

A/C light on is normal, dry warm air defrost beter than moist warm air.


  • 6 months later...
Posted

I agree with Bess, however, when you find the valve, just swap the 2 vacuum lines and voila, heat. However, do not forget to swap them again in the summer...............

I think I located the part in question. Is it about the size of a lighter with two hoses leading in to the bottom, and the electrical connection on top? If so, swapping the lines wont' do any damage?

Topped up coolant level, nothing. Swapped hoses, nothing. Still looking for options.

Yes, that sounds like the part. Swapping the 2 vacuum lines(hoses) won't work. You need to disconnect the electrical connecter and put an ohmeter across the solenoid terminals. If it is open(high ohms) as I suspect, then the solenoid is shot and needs replacing. As a temporary fix and to check the valve and heater core you could plug the two vacuum hoses together somehow and that should open the valve and allow hot water into the heater core.

Mine only has 1 vacuum line going to a diaphram,, the other line goes to nothing,, it is only about an inch long. Does anybody have a schematic that shows where the vac lines go? Its getting cold,, and I need heat.

  • 10 months later...
  • 1 month later...
Posted

I am having the same problem, I found the HCV but I am not sure how I am supposed to splice the vac lines together.

Is the vac line that runs from behind the engine supposed to be tee'd into the line running to the solonoid with some extra vac line? I attached a pic showing the HCV the red arrow is where I imagine you would T into the second vac line.

post-80382-1224354174_thumb.jpg

  • 3 weeks later...
Posted

had the same problem in my 93 sc300....no heat, just blew cold air. after much caution, i decided to try hooking the two vacuum lines together. INSTANT HEAT!!!! all i did was unhook the two small 1/4 inch tubes and tape them together with some electrical/duct tape. I plan on getting a new valve asap, just trying to find a new one at a good price.

Posted

I wish I went here first. I had a no heat problem about a year ago and took it to the dealer. I spent $3000 after they said they replaced the core. About 2 months ago, I had no heat again. This time I noticed my my coolant was low, added some, and had heat. Now I wonder if that was the problem before and I just wasted $3000. lol

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