2000 Buick LeSabre Custom

[ginhartmann]

I have a 2000 Buick LeSabre and the computer is saying it is the vacuum modulator, where is it located?

[carriedi]

is it giving you a code? what is the code?

what is your vehicle doing?

On old cars, they had a vacuum modulator on the trans for shifting. It would look sort of like a vacuum advance on a distributor. but it would be in the side of the trans usually close to the back. Newer cars use the TCM to control that now.

[ginhartmann]

It doesn't shift into overdrive. The computer says shift modular and the auto parts store is saying vacuum modulator. My husband would have to put it back on the computer to get the code. Is there anyway we can the blue print of transmission to see the location to figure out if it electrical or vacuum? Picture will also help with replacing the part.

[carriedi]

having the code that the computer sees as a problem would be the first thing to examine. everything else would be guessing. when ever you scan a vehicle you should write down all the codes to get. sometimes you may have a code that conflicts with other codes. and sometimes you may have things happen that are from the computer shutting things down in what is called limp mode. (in some cars if your check engine light comes on certain things are shut down to help insure that the engine can keep running. cruise control, AC, overdrive are all things that may be shut down if the check engine light is on)

[Gale77]

95 Buick regal, flushed,vacuumed ac system, then installed new compresser, accumulater,and office tube, system will not now take the freon without filling up with air, condenser was also flushed, where else can a restricted area be that causes the problem? It takes half a can then nothing.

[carriedi]

Maybe I am not understanding what's going on here. After all the replacements were installed did you evacuate the system? (put it under vacuum for 45 minutes) Then, after making sure there are no leaks, fill with your refrigerant?

what was the car engine doing while you were filling up the ac system?

[Gale77]

Yes system was evacuated. Clutch engages for a few seconds, and engine revs slightly, then goes back to normal idle, and then the system will not take any more freon, only air

[carriedi]

I still don't understand. what do you mean when you say "the system will not take any more freon, only air"? Where does the air come from? The ac system is a closed system. Once you evacuate the system all the air and freon are gone. It should be close to 30" of vacuum. The vacuum in the system will literally pull the refrigerant into the system. What are you using to put the refrigerant in?

the evacuated system will be empty except for some oil that will stay in the system. 28, 29,30 inches of vacuum, depending on your pump and how accurate your gauges are, should pull the refrigerant into the system because the refrigerant will be under pressure in it's container. There should be no air in the system and no way air can enter the system. (if everything is assembled correctly) So, I don't know whet you mean when you say "only air". Air from what or where? Are you charging it through gauges and going through the low side port? Is the high side valve closed? Low side open? When you go to charge it you have the engine turned off. Charge through both ports if you want too. Keep charging until the system stops accepting any more refrigerant. then close the high side valve. If you haven't charged 32 oz yet, start the engine now and turn on the ac to max air and low fan speed. The system should cycle and the low side should draw down below the static pressure of the refrigerant container. The ac system should turn on but if the pressure is too low it will shut off. Just wait, it should turn back on when the static pressure on the low side goes back up and the clutch should cycle on again.

95 regal should take 2.0 lbs of r134a. What do your gauges say when the system stops taking freon? What are the pressures? what are you using to charge it with? 12 oz cans, 30 lb bottle, through a gauge set? An after market can of freon with it's own low side adapter? let me know what you're working with.