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Discussion Starter · #1 ·
We have been having an intermittent problem with our air conditioning that has the local dealer baffled (admittedly in part because we can't reliably reproduce it).<p>Here is the general scenario: we drive our 2003 V70 for approximately 30--45 minutes, enjoying a nice cool comfortable interior temperature and the Climate Control Unit doing its thing on "auto" (with a/c switch on) to keep the temperature stable.<p>After that time, we begin to notice that the temperature has begun to rise and ther air is getting a little stale. I make sure "auto" is still engaged - it is. So I start to crank the fan speed manually. The fan speeds up, but no appreciable air comes out any vents. It's as if all the vents were closed. So I set the vents to the defroster vents - no air flow. I set the vents to just the dash vents - no air flow (or barely anything). I set the temp to minimum - no air flow. I set the temp to maximum - no air flow. I can hear the fan going hard inside the dash (over on the passenger side, behid the glover compartment somewhere), but no matter what setting I put the system on, and no matter how fast/hard the blower is blowing, no air is coming out the vents. <insert head banging brick wall here><p>Sometimes, by pulling over to a rest stop and turning the car off and on, the problem will go away (for a while) (isn't "reboot" the answer to everything?). Sometimes my wife has noticed that disengaging the a/c switch, and then reengaging a little while later, seems to fix the problm for a while. Don't know if this is coincidental or not.<p>Dealer has flashed/upgraded the software, to no avail (wrote me a nice note about how "auto" works - thanks). Once we hobbled the car over on a Saturday night just as they were closing to prove to them that it does this - they noted it, said "Hmmmm...that's odd", did all of the above to no avail, and said make an appointment. Of course, the problem did not surface during the appointment....<p>Anyone experience this? The car, other than this issue, has been great, but as I approach the end of the warranty period, I am concerned we are not going to find the answer. I am also concerned as it gets hotter here in the northeast that his will happen at the wrong time on some wicked long family trip.<p>We purchased the V70 in part because the a/c was going to be such a step up fom our venerable 1990 240. This issue has us really perplexed and a little "bummed out" (since we hooked up the USA*SPEC iPod adapter, the car has been otherwise perfect for us).<p>I have searched forums here and elsewhere and haven't found any similar complaints, but maybe different search terms might have revealed something (just in case someone says "Duh, there are forty threads on this, search is a great feature, etc." lol).<p>RCM<br><BR><BR>
<i>Modified by rcm at 11:25 AM 6-19-2006</i>
 

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Re: Intermittent Vents / Blower problem (no air comes out) in 2003 V70 (rcm)

My coworker's V70 did this. I forget exactly what was replaced but they pretty much replaced anything that is connected with the A/C because they couldn't fault trace it. Under extended warranty of course.
 

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Re: Intermittent Vents / Blower problem (no air comes out) in 2003 V70 (rcm)

1st thing to do is to run your A/C <B>in manual</B><br>the middle vent <B>to face </B>pushed, (red), temp on full cold to see if the A/C holds up and then get back to us.<br>Let me know if this works first, if it does, it's a bad temp sensor
 

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Re: Intermittent Vents / Blower problem (no air comes out) in 2003 V70 (rcm)

Exact same situation as you. <br>Dealer fixed it by replacing Temp Sensor #30665118 near the evaporator. <br>$40 part and $10 labor. <IMG NAME="icon" SRC="http://********************/smile/emthup.gif" BORDER="0">
 

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Discussion Starter · #5 ·
Re: Intermittent Vents / Blower problem (024tnfi)

Thanks for the responses.<p>Re: JRL's troubleshooting suggestion above, we have tried putting the unit off manual, just front vents, full blast blowers (i.e. turning the blower speed dial to max) and only minimal air comes out the vents - but the air that does come out is cold, as in the A/C itself seems to be working. <p>It was around ninety degrees this weekend, and we did a lot of driving around, so we were able to try lots of things. We still can't get the system to go into the strange mode at will - i.e. it only seems to happen after about 30 minutes of driving.<p>However, my wife was able to determine (I give her the credit on this) that if, after we start to notice that the system seems to be exhibiting the eratic behavior, we turned OFF the A/C, we found that the internal vents seemed to then open and permit more air to be pumped into the cabin, at which point (usually after 10 or 20 seconds) we would turn the A/C back on again, and the unit seemed to continue to operate normally (i.e continue to pump more than minimal air into the cabin, with the A/C on), at least for a little while.<p>That doesn't get me any closer to what the problem is, but at least we figured something out to do as we start to swelter on the highway.<p>I like the idea that a temperature sensor could be swapped out - our car is still under warranty too. Does anyone else think that could be the culprit/cure? How do I go about convincing the dealer to try that?<p>RCM<p>
 

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If it's under warranty, then the dealer should do/try EVERYTHING to get everything back to running correctly and stop giving you any run-around. If your dealer won't do that, take it to another.
 

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Re: Intermittent Vents / Blower problem (no air comes out) in 2003 V70 (rcm)

Your evaporator is icing up! <p>What you describe as being able to operate for a time period and then it slowly loses air velocity is the real clue. If you stop for a while, and the ice melts a little from the evaporator, than you are fine, or at least improved, again.<p>The temperature sensor that needs to be replaced is the evaporator temp sensor. It's only function is to shut down the AC compressor if the evaporator temperature is too low. The evaporator temp is to be held at +1 to +3 degrees C. It must not allow freezing. Note that this has nothing to do with the cabin temperature sensor which is a different sensor entirely. <p>When you stop the car, do you see an unusual amount of water from underneath the car? (right in the middle of the car basically). <p>Something is allowing the system to ice up, be it the evaporator temp sensor, restricted air into the system (dirty filter?), a faulty door motor, low refrigerent, etc. My money is with what the other folks have stated here, the temp sensor.<p>You do want to make sure it is fixed, and that you see proper water flow under your car. You do not want the evaporator sitting in water as it will corrode and they are high dollar, (mostly labor), to replace.
 

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Discussion Starter · #8 ·
Re: Intermittent Vents / Blower problem (rogersampson)

Interesting - I am on board with your diagnosis, and in fact I have seen a puddle about mid car (i.e. halfway back, I think on the drivers side but I will look again to confirm where it is). <p>With my old 240, we had to make sure we did not keep the A/C on full all the time to keep it from freezing, but there (upon freezing) the vent speed was the same, but the temperature rose.<p>My uninformed question - in the V70 why does upon freezing the air flow itself slow down, even as the temperature of the little air that does continue to come out seem to still be cold? (I don't have a good mental picture of how this works, obviously).<p>RCM
 

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Re: Intermittent Vents / Blower problem (rcm)

The evaporator must have air blow through it in order to remove heat from the air, before that air is passed into the cabin. <p> Physically it is much like a heater core or a smaller version of your engine radiator. The refrigerant enters the evaporator as mostly a liquid, and then boils and converts to a gas state (evaporates) as it leaves the evaporator, carrying with it the heat that was removed from the input air. Remember refrigeration removes heat, as opposed to making things cold. Formulas will work much better if you keep this in mind as well. Since it is an air to refrigerant heat transfer if the honey comb core is blocked by ice it impairs the air flow. <p>In regard to your older car having this issue and you not seeing a decrease in air velocity, I really have no answer other than perhaps the icing was not as severe? Clearly in either case the fan motor will keep running at what ever speed it is set. If the fan can not blow air through the evaporator it will reduce the nozzle (vent) velocity. As it occurs you may also get bits of ice being blown out of the nozzle. Perhaps the newer car HVAC system is tighter, which just means you hear the fan running, but since it really can not move air, it just serves to increase the static air pressure in the system. You may see more water come out of the bottom of the car as this occurs. <p>My money is still on the evap temp sensor, or perhaps the expansion valve which is what meters the refrigerant into the evaporator. <p>All the above is pretty common stuff for a competent AC person. I am sure they will get it.
 

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Intermittent AC problem - ambient air

I have a similar problem to the one originally posted by rcm. I have a 2001 V70. We had the same intermittent problem with the AC where it would start blowing ambient air. We did not have the low airflow complication mentioned by rcm. My mechanic replaced the evap temp sensor. Not long afterwards the problem reoccured. Additionally, we have noticed the engine water temperature rapidly increasing at the same time the AC experiences problems. Any thoughts?<BR><BR>
<i>Modified by eapowers at 6:23 PM 6-27-2006</i>
 

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Re: Intermittent AC problem - ambient air (eapowers)

If the system worked for a while, and then quit, it soulnd like a refrigerant leak. I bas this on the fact that you stated it did work for a while, but it know blows ambient aiAirflow is OK.<p>The fact that the engine is running hotter is a tougher call. Does this only occur when the AC is activated? A remote possibility is a failed compressor that is putting an excessive load on the engine.
 

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Discussion Starter · #12 ·
As an update, we had the car serviced this weekend, turns out the computer was "throwing a code" for the Evaporator Temp Sensor (it wasn't last fall when this started) . This made convincing them to swap it out very easy, although after I discussed the symptoms (i.e. before the computer was even checked), the Service Rep agreed that the Evaporator Temp Sensor was the first thing they would try.<p>Seems to have worked - we drove for extended distances over the July 4th weekend in 90 degree weather, and the A/C continued to work the entire time. Thanks to everyone for your thoughts and diagnoses. I'll will update again in a few weeks to let everyone know if this fix sticks for us.<p>RCM
 

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I have similar problems. Aircon fades after 15 minutes, then, after switching off and waiting 15 minutes, works again. If it is the temp sensor, where do I find it? I've wired 12v directly to the clutch and it clicks in fine for a few times, then doesn't seem to have enough pull to engage the clutch properly, although I can still see the clutch moving a small amount as if it can't quite make it.. This is the same with or without the engine running. I am slightly confused about how the compressor is wired: there is a feed from the relay (in the LH fuse box) which goes into the back of the compressor, and there is also a second wire which connects to a small square black thing attached to the side. What is it and how is it wired in? If the clutch is faulty, can it be bought seperately and can it be fitted without disturbing the compressor?<br>Forgot to mention, its a 1997 V70tdi.<p>Any help appreciated!<br>Dave<p><br><i>Modified by dave perrett at 10:20 AM 7-8-2006</i><BR><BR>
<i>Modified by dave perrett at 10:21 AM 7-8-2006</i>
 

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Re: (dave perrett)

Update on my aircon problem. The clutch needs 12.5 volts to engage. However, if it is kept engaged it begins to heat up and after 2 minutes it needs 13.5 volts and after 5 minutes it needs 14.5 volts - it seems to stay at that from then on. Therefore, the clutch does not re-engage until the aircon is switched off and left for 15 minutes for the electro-magnet to cool down. Once engaged, the holding voltage requirement is only 5 volts, and it will stay engaged indefinately.<p>I began to wonder whether there was a component in the compressor which cuts down the voltage once engaged to stop the windings overheating, and it was this that was faulty. Nobody seems to know! <p>So, I went to Maplins and spent £11 and built myself a simple timer circuit and relay so that when the aircon switches on the clutch gets the full current and engages, but after a couple of seconds a 6 ohm resistor reduces the current to a holding voltage. <p>And it works! Clutch engages when required, stays on as long as the control unit asks it to, and re-engages when needed. Aircon as good as new. Not bad for £11. I don't know how long the fix will last, though!<p>Hope this is helpful to someone! Any comments would be gratefully received.<p>Dave<p>
 
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