89REATTAJIM Posted July 21, 2006 Posted July 21, 2006 Scenerio: Leave work in afternoon, a/c set to automatic @ 74 degrees. Ambient temp 95. Interior temp 115 or so. A/C blows on low with cool air for about 10 minutes then fan switches to high & starts putting out colder air (or maybe just higher volume). Any thoughts on why there is a 10 minute delay for hi speed to kick in??? <img src="http://forums.aaca.org/images/graemlins/confused.gif" alt="" />
Reatta45 Posted July 21, 2006 Posted July 21, 2006 If you manually select hi fan, will it go to hi? In a 91 in diagnostic you can read out the voltage output to the fan at BCM data BD20? (I think that diagnostic point is also available on other years?)If you can get that reading it should be battery voltage while in hi? if it is less than full battery the BCM is not putting out the right voltage. If that voltage is right then it is a blower motor problem, possibly brushes worn out, or hanging up. KennyV.
89REATTAJIM Posted July 21, 2006 Author Posted July 21, 2006 "If you manually select hi fan, will it go to hi?" No. Kept closer watch today. After minute or two of driving, dash outlet read px 62 degrees. Again about 10 mins later, fan went into hi & outlet temp pulled down to 50. Stayed around 48 - 50 'till stopped for traffic lite - crept back to 60. Back up to speed temp dropped to 50 again. Stopped at bank for 15 mins. Started car back up, fan went to hi right away. Kinda like a 10 minute delay when car doesn't run for a few hours. Don't think it's a low voltage issue, thinking more like a relay somewhere.?
Reatta45 Posted July 22, 2006 Posted July 22, 2006 I may be wrong about the pre ?91 cars? but I thought they used the same cabin temp control system as a ?91, with just a different way to get to it and display things? My climate control system allows you to interface with the BCM, this allows you to see the variable ?command voltage? at the BCM diagnostics BD20. On the ?91 there is no relay for the blower fan, it is variable speed because the BCM sends a variable voltage to the blower motor. I can not think of any good reason to have a delay for the AC to go to high, I do know that there is a temperature that needs to be satisfied before my car will go to hi speed blower in the winter for heat? Someone that knows the earlier climate control system may have a thought as to what is happening with yours? KennyV.
jonlabree Posted July 22, 2006 Posted July 22, 2006 Is this a 90 0r 91??My 90 did something like what you are talking about. I took the control apart and cleaned it, put it back together and it has worked finr ever since
pkmike Posted July 22, 2006 Posted July 22, 2006 What control did you take apart and clean?? My 89 does the same thing... about a 10 min or so delay on the hi fan coming on.
Roadster90 Posted July 22, 2006 Posted July 22, 2006 Glad you folks have brought up this subject....I have a 90 coupe and I don't think mine has 2 speeds...can some one tell me how find out if I do as it is not very efficient compared to other cars (in 95* > temps you are uncomfortable)Thank you....
jonlabree Posted July 22, 2006 Posted July 22, 2006 On a 90, right above the Radio is the temp control. Remove it and take it apart and wipe all contacts inside with alcohol and put it back together.Mine was not letting me change the temp down all the time and sometimes it would not work at all. After cleaning it works evertime.
89REATTAJIM Posted July 22, 2006 Author Posted July 22, 2006 Sounds like a good fix for a '90 - '91, too bad it won't work on an '89. Even if I could get to the inside of the CRT, the alcohol would probably be harmful to the phosphors. <img src="http://forums.aaca.org/images/graemlins/wink.gif" alt="" />
jonlabree Posted July 22, 2006 Posted July 22, 2006 Jim, We have the same likes. I can never get the order straightened out either.Jon... <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />
Roadster90 Posted July 22, 2006 Posted July 22, 2006 I have another question...must be I am not understanding something correctly or I am explaining myself wrong...On the cowl a/c-heater blower fan, if it operates on the 3 or 4 different positions on the climate control panel, is there a secondary high that is controlled by a thermostat or the climate control system that is supposed to operate as a "high" speed ? Last year I removed the fan from the cowl and vacuumed, hosed out, and/or cleaned every bit of foreign matter out... I also stopped at a freon station and they checked my R12 and told me it was at full capacity.....My fan in the coupe works on the several speeds printed on the climate control facia, but the high is not as hign as the one in the convertible for some reason. Sitting at a stop light, in gets very uncomfortably warm in the cabin...Any suggestions please.....
jonlabree Posted July 22, 2006 Posted July 22, 2006 Have you cleaned the Evaporator which is under the ECC power module. Whenit is restricted it will cut down the volume of air coming thru the vents when the AC is on..Jon...
Roadster90 Posted July 23, 2006 Posted July 23, 2006 Sure did Jon...That is the same housing as where the fan is....removed the module and fan/motor assy, picked it clean, blew it out, hosed it out (with a bleach mixture), etc and so, on until it was squeaky clean (lot of leaf material in there) <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" />...actually did not notice a difference at all when finished <img src="http://forums.aaca.org/images/graemlins/confused.gif" alt="" />
jonlabree Posted July 23, 2006 Posted July 23, 2006 In that case I would try a new blower motor. <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />
jonlabree Posted July 23, 2006 Posted July 23, 2006 P.S. Thank you for the payment. I didn't expect that much.
Reatta45 Posted July 23, 2006 Posted July 23, 2006 Nic?If you set the temp to 60, (as low as it will go), the ?air mix door will be fully closed and the ac system will be set to recirculation? If your temp is at anything other than as low as it will set, you will NOT be at recirculation and the blower motor will not ?seem? to be moving as much air as it would if the system was in fact at recirculation. On a 90 or 91 you can check if the blower motor is being driven with full battery voltage (hi speed) by going to diagnostics BCM data, BD20 should read full battery voltage, mine reads 13.3 at idle RPM with ac set to high fan speed before going into diagnostics data? You can also check the air mix door position at BD22 and BD23. Hope this makes sense, KennyV.
Roadster90 Posted July 23, 2006 Posted July 23, 2006 Kenny,,,,Yes it makes a great deal of sense. I have copied the reply and will attempt diagnostics this coming week (have finace with me this weekend)....Thanks,,,Nic
harry yarnell Posted July 23, 2006 Posted July 23, 2006 If you want to see the condition of the evaporator, don't go thru the fan housing; pull the blower controller on top of the plenum, just behind the power steeing pump. Three 7mm (hex) sheet metal screws, and out it comes. Look down this hole with a light, and there's the evaporator staring at you.
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