No vacuum to the heater control valve

[Kai]

Had no heat recently, and unfortunately, in this climate, thats a no-no.

The heater slider does absolutely nothing. The only way i can stay warm, is to put the system into 'recycle' mode and keep breathing.

If i push the solenoid arm into 'heat' position, and clamp the pipe, it'll stay up. The moment i release it, it returns to default position.

Theres just no vacuum coming from the pipe that connects to the top of the valve whatsoever. Am i looking at a simple 'dead valve' assembly, or something far more serious?

Cheers and TIA

 

[black89t]

i would replace the plastic hard line with regular vacuum line. its most likely cracked. also make sure you can blow through it first though. also the t. vacuum ports and lines can get clogged.

does you stock boost gauge show boost? they share the same vacuum sorce.

 

[tissimo]

Have you bypassed the VSV?

It was 68* this morning and I need to fix mine as well..

 

[Kai]

Nope - system is stock, and i'd like to keep it that way if possible, rather than just bypassing it.

What size ID vac line do i need - 3mm?

 

[tissimo]

Nope - system is stock, and i'd like to keep it that way if possible, rather than just bypassing it.

What size ID vac line do i need - 3mm?

Bypass it to test, most likely the vsv has died and needs to be replaced.

 

[black89t]

^he said he has no vacuum to the line.

 

[GrimJack]

Actually, he said there is no vacuum at the top of the valve, which is post VSV.

So, first we need to work out whether it's a problem with the vacuum source, or whether it's electrical.

Pull the vacuum line off the input on the VSV - that's under the valve mounting bracket unfortunately, but you can hire a small child and grease up their fingers if need be. Or get double jointed extra long needlenose pliers. However you get that off, check if it has vacuum. If not, chances are the problem lies in the vacuum source - replace some lines as mentioned above.

If you get vacuum there, the problem lies in the electrical. Pull off the electrical connecter to the VSV and hotwire it with 12v direct to the battery and a long test hose connected to the vacuum input line. Try to blow through the hose while toggling the power... you should notice the input line going from open to closed and back. Be especially careful to get the input line - the one that connects to the line running across the front of the firewall - as the output line is always open one way or another and will screw with your test results.

If the VSV is working, then there is a problem with your climate control, fan control box, or wiring. This is a bit rare, so do those steps and get back to us, and I'll continue on the subject of those if you need it.

 

[Kai]

Yeah theres vacuum going IN, but there's no vacuum SWITCHING going on. I swapped the vac lines, so that the input it going straight to the vacuum chamber, so the matrix now has hot water flowing through it...but still no hot air, even after the engine is up to temp.

Remember - RHD car means that the VSV is a piece of piss to work on.

I've just re-soldered the connections on the heater control PCB (it's little more than a few buttons, and a slider pot) as well - so unless the PCB itself is toast...

 

[GrimJack]

Or the actuator that moves the slider is toast. Time to scrunch down into your footwell and move the heater control from hot to cold and back while peering at the actuator arm with a flashlight in your teeth...

 

[Kai]

Not as cramped in a RHD

Where should i be looking at though?

 

[IJ.]

The Mixer door is controlled by a Servo motor so it's not just a case of moving the arm

It's either a dead climate control or a dead amplifier Kai.

 

[GrimJack]

Actually, I think it's more cramped in a RHD. It's near the firewall on the top of the transmission hump - in LHD cars you can see it from the passenger side footwell if you have a good light. Not sure if all the ducting is in reverse on the RHD cars...

 

[Kai]

I think the ducting is somewhat different, due to the position of the blower motor. The climate control is just dead simple - literally a potentiometer, and some switches - theres no real electronics in there, unlike the US model.

Is it common for the A/C amp to just fail?

Going to check to see if theres a blockage in the heater matrix though, could be that its just clogged?

 

[IJ.]

Yes I've been through 2 of them, the CC has some smarts but a lot of the time it's a dirty linear pot that can be "fixed" with some C0 cleaner.

 

[Kai]

Hmm, i'll have a poke around today, i'm in 'limp around' mode at the moment.

 

[Kai]

IT WORKS ONCE MORE!

Resoldered EVERY SINGLE JOINT in the heater control panel, took out the air mix control servo (not a job for those of you that have headaches/migraines etc - dangling UPSIDE DOWN with your head wedged into the footwell = GRRR!!!), cleaned the filthy contacts in there, and re-vaselined the contacts, and reassembled...the VSV works as intended now!

Finally, lovely, lovely heat!

 

[IJ.]

Nice save

 

[Kai]

Yep - although, i will NEVER AGAIN want to remove the air mix servo...fucking thing is a PAIN IN THE ARSE to get at. Involved me dangling UPSIDE DOWN, one leg out the door, my busted one draped over the armrest, my head cocked to one side whilst wedged under the lower dash support bar and my arm wrapped around it, holding a magnetic probe IN MY TEETH.

I also came away feeling rather unwell - tramadol + gabapentin + being upside down = wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

And then Migraine.

 

[IJ.]

Now you begin to understand why I've gone for an aftermarket HVAC in my car

 

[Kai]

Well, now i can understand that no-one else besides the Japanese (with the possible exception of the Germans) could have built this car...but then, it's the only car i've ever owned that's had A/C...