With thanks to Gary T From TheStraightDope.
Mike,
it looks like your battery is knackered. Test it by following Gary's procedures below or perhaps just buy a new one.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If it's a serviceable battery, remove the vent caps and test the specific gravity of the electrolyte fluid. A tester for this is pretty inexpensive ($5-10?). A difference of 30 points between any cells is suspect, a difference of 50 is bad (replace now). If there's not enough liquid in the cells to fill the tester, bring them up to their full mark with clean water and wait a day or two for it to mix in. If the liquid is below the metal plates inside, buy a new battery now.
Other tests require pricier equipment or trickier procedures. A load test can be done with a load tester, or by disabling something to prevent the engine starting and then cranking it for 10 seconds, in either case reading the battery voltage at the point it's been under load for 10 seconds. Starting with a fully charged battery (12.6 v), it should read at least 9.8 v for the load test - but if it's close to that, it's weak. Really good batteries read over 11 v.
SOURCE: AC blows hot air
try this website fix & troubleshoot heating & A/C www.automedia.com and another car A/C repair www.directgardening.com
SOURCE: rpms drop when defrost or ac is on
Then you need to scan your onboard computer network. Your A/C compressor is controlled by your Powertrain Control Module (PCM) and the HVAC Control unit controlls the rest of your HVAC system and communicates with the PCM when A/C requests are made. Apparently, somebody is either not getting the message or the PCM is unable to control the throttle like it is supposed to.
SOURCE: rough idle on 2004 trailblazer when ac is on
Hello
The engine
and transmission in this cars drive train are fully
electronically controlled by a computer called the PCM (Power Train
Control Module). Whenever a problem like this occurs the computer
stores a record of the problem (there are of course some exceptions
to this, like the fuel pump for instance) in the form of a fault code
in its memory, to read these fault codes you must have the systems
memory scanned with a special tool. Once the fault code(s) are read
you then must perform the appropriate diagnostic testing to find and
resolve the problem(s) DO NOT REPLACE ANY PARTS UNTIL THE
DIAGNOSIS & TESTING IS COMPLETED.
SOURCE: rough-idle-when-ac-is-turn-on
Hello The
engine and the automatic transmission in this vehicle are computer
controlled and in most cases when a fault occurs a fault code is
stored in the memory of the computer control module. There are
exception to this, such as the Mass Airflow Meter and fuel pressure
problems. What must be done is to have all the basic testing done
such as a scan of the system for fault codes as well as a check with
a live data scanner tool for engine functions that are not within
range of normal, a trained technician is required to know what is
correct and what isn't, then based on careful diagnostics done from
a factory repair manual the correct part is replaced or the wiring
repaired or the computer replaced (known as the PCM), which is very
rarely the problem. Other basic checks must be done as well such as
mechanical problems with the engine as well as engine state of tune
and mileage on the engine. The transmission can have mechanical
issues as well such as no gear engagement at all or a filed pump or
other pressure related problems.
SOURCE: Finding the idle goes up n down/die out when using Defrost
Sounds like a vacuum problem. Do you have a seemingly hard brake pedal? If you do chances are your brake booster is leaking vacuum. If not check your vacuum lines. Your heater system is controlled by vacuum.
127 views
Usually answered in minutes!
Hi Mike Potarf, I want to help you with your question, but I need more information from you. Can you please add details in the comment box? What vehicle, is this a Trailblazer by chance?
×