Had the battery leak and damage the vacum lines on my '99. I repaired everything (I thought) and still I cannot get the air to come out the top vents..still on the bottom. I have only two lines coming out of the check valve... It appears that one is going to the dash and the other into a harness that goes to the back of the engine. My "99 service manual only shows two lines coming of the check valve, but one of the lines brances off into two lines...cannot find this unless it is inside one of the harnesses. Nevertheless, I am still not getting vacum from the engine....where is a good place to pick up engine vacum so I can at least see if I have the other line repaired correctly. Any other advice or info is welcome!!!

Thanks

 

Are you talking about the check valve down by the PCM which is right next to the accumulator?

You should have one small line coming off the back of the intake manifold, this line goes into the main wiring harness where it runs inbetween the engine and firewall and as soon as it gets past the battery it exits the harness and plugs into the junction by the check valve.

Down where the vacuum accumulator and check valve are located the vacuum source branches off and some of it is routed thru a solenoid valve to operate the air pump and then some of it goes thru the firewall to the HVAC module.

You might be able to check for vacuum at the HVAC module by locating the purple vacuum line which is the source coming in to see if you have vacuum while the engine is running.

 

Yes..that is the check valve I am talking about. There is small plastic tank with a short vacum line off the bottom which the check valve is connected to. There are two lines connected to the check valve... one looks like it goes into a wring harness and through the firewall and the other into a wiring harness and to the back of the engine. I am not shure where the solenoid is located?

 

same thing here for me, but I haven't attempted to fix it yet...

 

If you follow the vacuum line straight up it's mounted to the wheel well liner but it's strictly for the air pump, it will have no effect on the HVAC.

I would check the line for vacuum that is coming from the back of the engine, if you start the engine and it is pulling vacuum then connect everything and check it under the dash where it comes to the HVAC module. You might even want to remove the glovebox for better access (it only takes about 5 minutes), you'll see the plastic line connect to a purple hose which goes to the vacuum solenoid on the HVAC module, if it's pulling vacuum there then you may have a problem with the vacuum solenoid or one of the vacuum actuators on the HVAC module.

There are 2 vacuum actuators on the module which control the position of the doors for airflow up/down and then there are 2 electric actuators which control mode doors that seperate the passenger and drivers side.

 

I had the leaky battery, and it melted the vacuum lines. I cleaned up everything and pieced the melted lines, and all was okay - for awhile.
Then the vacuum quit again. Seems the acid had been sucked into the lines, and continued to eat them from the inside out, and the goo clogged the line.
I agree with the guys above, start at the purple hose under the glove box and check for vacuum there. Then work back.

DG

 

Yes, acid will melt the vacuum lines.
1) Source of Vacuum: Comes from the MAF sensor on back of intake manifold
2) Destination: Vacuum control head in passenger compartment via the check valve on the vacuum resivoir located in passenger wheel well near the door inside the fender.
3) What to do (this is what I did): Take out the battery. Find the source vacuum line in the wiring harness coming from the engine area into the battery compartment. Cut back as much of the vacuum line as you dare, you're going to splice it here. There's a large rubber grommet on the firewall behind the battery, that's where the supply vacuum line enters the passenger compartment. Find and cut the damaged vacuum line leaving enough good line sticking out of the grommet so you can splice it. Get 1/8" emission hose and splices from your local auto store. While you are at it get a new check valve from the dealer. Put the car on jacks and remove the passenger wheel well access panel to get to the vacuum resivoir and check valve. (I also bought 5/16" ID rubber fuel hose to encase the vacum lines as added protection through the battery compartment). Splice the source line and run to the vacuum resivoir. Install the new check valve (Middle fitting goes on bottom of resivoir). Connect the source line to the bottom fitting on the check valve. Attach the supply 1/8" hose to the check valve top fitting and run up into battery compartment. Splice where you cut the line near the grommet. NOW TEST IT before you begin to button her up. If all works, secure the new vacuum lines to the wiring harnesses using cable ties. TEST AGAIN in case some thing came loose. Now is a good time to asses the dammage from the leaking battery: Look at the PCM area for damage. Spray everything down with CRC Battery Cleaner, nuetralizes acid and is easier too clean up than baking soda. If everything is OK put wheel access panel back, get her off jacks, install battery (Hopefully a new gel Gas Mat type, non liquid electrolyte type). TEST AGAIN. If it works you are good to go.

Did this twice, battery leaked again, bought a Optima Red Top and encased the vacuum lines in rubber fuel line for added protection. Working for a year now. Good Luck!

 

Actually the source of the vacuum is from the back of the intake but it's right next top the MAP sensor, the MAF is in the intake tract between the throttle body and the air inlet.

 

Yep, slip of the finger, it's the MAP sensor for vacuum source.