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Projects - 2001 and 2003 TC

dweiss

New member
20
3
3
My dad passed away a few months ago. He loved Town Cars and had several over the years. I've been working on miscellaneous issues on his 2001. The air suspension has completely bottomed out. I checked swapped all fuses and relays, then found an air compressor at the junk yard - I bench tested both old and "new". The old was shot (locked up) and the junkyard part sounds ok. It comes on and pressurizes the system (when I apply 12V directly), so I know there are no leaks to the solenoids, but it does not operate automatically. Thinking it was the leveling switch, I replaced that today with a junkyard part. It did not come on, so either the switch is bad (or possibly damaged when coming off the lift as the suspension is still bottomed out). I got another junkyard leveling switch, and I'm thinking this time of NOT turning off the suspension when on the lift. That way if it works, it will partially fill and not damage the switch when lowered. Any thoughts of other areas to check first? For example, does the system require sensor inputs regarding doors closed, etc. before it will operate?

The second Town Car is a 2003 Cartier which my mom still drives. Both AM and FM give static (no stations) with engine off or on. I'm assuming it could be the antenna module. I pulled an antenna module (amplifier) from a 2003 Signature at the junkyard today. It's located under the headliner next to brake light. I would like to have a better procedure for removing the corner piece that contains the shoulder belt. The only online info I found said to pull it. While it seemed to work at the junkyard, the one in my mom's car seems tighter. I don't want to mess up the mounting clip if there is a better way. Then I can pull the headliner down to expose the screw holding the module. Any thoughts on this? Thanks in advance!
 

04TC

Junior Member
77
10
8
Tampa, FL
I got another junkyard leveling switch, and I'm thinking this time of NOT turning off the suspension when on the lift. That way if it works, it will partially fill and not damage the switch when lowered. Any thoughts of other areas to check first? For example, does the system require sensor inputs regarding doors closed, etc. before it will operate?
I wouldn't raise the car with the air suspension switch on; it can be a safety issue. That is why the manual says to always turn the air suspension switch off before raising the car or servicing it. After you lower the car you can turn it back on.


For the 2003, what sound system do you have, is it the premium one or the standard one? If I recall correctly, the standard sound system which is the one in my (2004) car has the antenna inside the head unit itself? Do music CDs work. The premium head units tend to not last as long as the base ones. Sorry I can't be of more help.
 

dweiss

New member
20
3
3
As for the 2001, I am hoping that with the springs completely bottomed out (upon lowering the vehicle) that the leveling switch is not damaged. It would be great to have an air spring R/R procedure as I am sure they address filling of new air springs and I could apply that logic here.

The 2003 has AM-FM/cassette/CD with multi-disc option for trunk. I don't know if that's premium or not. Music CD's sound great, but just a low static hiss on ALL radio stations with engine off and perhaps a little noisier with engine on. I installed the used antenna amplifier module today (the one under the headliner next to brake light) and it made no difference. My guess is to pull the radio and check for bad connections with antenna cable (or perhaps plug in another antenna to see if there is any better reception).
______________________________
 

Town

Senior Member
4,400
133
63
Ottawa Ontario Canada
Welcome to the Forum.

The air suspension is controlled by a module behind the glove box, that also controls the EVO power steering. There are two distinct connectors for the module. If the module sees a problem it will light up a warning in the message center. The warning is lit also by the suspension switch in the off position. The module looks for a signal from the height sensor as: trim height or above or below trim height. When parked the module responds instantly to the trim height and adjusts air spring pressure accordingly. When the car is moving there is a 45 second delay in trim height changes due to normal suspension movement. If the suspension height sensor reading is below trim height setting (suspension low) then the compressor is switched on and the spring solenoids opened (there is a T that connects compressor line to each spring solenoid. When the suspension raises the height sensor will signal trim height and spring solenoids are closed and then compressor power is turned off. If height sensor indicates suspension is above trim height the vent solenoid (part of compressor) is opened with the spring solenoids to lower the suspension height to trim height when module closes the vent solenoid and the spring solenoids. It is important that the air in the system is dry which is controlled by a replaceable drier fitting containing a desiccant at exit of compressor. This drier can get waterlogged and prevent all air flow needing the desiccant to be removed and dried in an oven or the drier unit replaced.

Ensure the suspension switch is in off position for safety since the system will be disabled while working on it.

When the suspension is collapsed the air input to the air springs may be cut-off so even a fully working system will not raise the car. So the first thing is to jack the car up off the bump stops a few inches Less than the trim height of 4" from top of axle to underside of frame rail above bump stops. The 2001 model height sensor should not be affected by a collapsed suspension. The single height sensor is a telescoping unit that resembles a covered shock, but it can be bent into somewhat of a U shape. So check the height sensor, it can sometimes be straightened.

Connect up your new compressor. Turn on the suspension switch and then the ignition switch. The compressor will operate to raise the car with the doors open but it will not vent the suspension to lower the car (to avoid grounding the body on kerbs or hurting a person exiting or entering car. So car should raise if everything is working correctly.

Assuming the car does raise to trim height then switch off the suspension and jack up the body to inspect the air springs. You are looking for cracks that have widened. Mix a spray bottle with soap and water and spray the mixture over springs and solenoids to check for bubbles indicating a leak. Replace air springs and use new solenoids. We have the procedure to replace the air springs in out Tech forum here: Town Car rear air suspension spring replacement

To replace the height sensor we have a procedure in our Tech forum here: Town Car air suspension height sensor replacement and adjustment that contains suspension height settings too.

Let us know if the system does not turn on the compressor, etc.
 

04TC

Junior Member
77
10
8
Tampa, FL
I believe the following is the premium sound system for the 2003:

6313
The following is another premium one but I think is for later models (note it says Soundmark):

6314
The non-premium head unit looks very similar to the one in the first picture, except 1 or 2 of the buttons are different, and it doesn't have the Alpine logo on the tape slot. (I wasn't able to find picture online of the non-premium one, so I am working from memory as I replaced the head unit in my car a while back)
 

dweiss

New member
20
3
3
I believe the following is the premium sound system for the 2003:

View attachment 6313
The following is another premium one but I think is for later models (note it says Soundmark):

View attachment 6314
The non-premium head unit looks very similar to the one in the first picture, except 1 or 2 of the buttons are different, and it doesn't have the Alpine logo on the tape slot. (I wasn't able to find picture online of the non-premium one, so I am working from memory as I replaced the head unit in my car a while back)
I think she has the premium stereo - first pic.
______________________________
 

dweiss

New member
20
3
3
Welcome to the Forum.

The air suspension is controlled by a module behind the glove box, that also controls the EVO power steering. There are two distinct connectors for the module. If the module sees a problem it will light up a warning in the message center. The warning is lit also by the suspension switch in the off position. The module looks for a signal from the height sensor as: trim height or above or below trim height. When parked the module responds instantly to the trim height and adjusts air spring pressure accordingly. When the car is moving there is a 45 second delay in trim height changes due to normal suspension movement. If the suspension height sensor reading is below trim height setting (suspension low) then the compressor is switched on and the spring solenoids opened (there is a T that connects compressor line to each spring solenoid. When the suspension raises the height sensor will signal trim height and spring solenoids are closed and then compressor power is turned off. If height sensor indicates suspension is above trim height the vent solenoid (part of compressor) is opened with the spring solenoids to lower the suspension height to trim height when module closes the vent solenoid and the spring solenoids. It is important that the air in the system is dry which is controlled by a replaceable drier fitting containing a desiccant at exit of compressor. This drier can get waterlogged and prevent all air flow needing the desiccant to be removed and dried in an oven or the drier unit replaced.

Ensure the suspension switch is in off position for safety since the system will be disabled while working on it.

When the suspension is collapsed the air input to the air springs may be cut-off so even a fully working system will not raise the car. So the first thing is to jack the car up off the bump stops a few inches Less than the trim height of 4" from top of axle to underside of frame rail above bump stops. The 2001 model height sensor should not be affected by a collapsed suspension. The single height sensor is a telescoping unit that resembles a covered shock, but it can be bent into somewhat of a U shape. So check the height sensor, it can sometimes be straightened.

Connect up your new compressor. Turn on the suspension switch and then the ignition switch. The compressor will operate to raise the car with the doors open but it will not vent the suspension to lower the car (to avoid grounding the body on kerbs or hurting a person exiting or entering car. So car should raise if everything is working correctly.

Assuming the car does raise to trim height then switch off the suspension and jack up the body to inspect the air springs. You are looking for cracks that have widened. Mix a spray bottle with soap and water and spray the mixture over springs and solenoids to check for bubbles indicating a leak. Replace air springs and use new solenoids. We have the procedure to replace the air springs in out Tech forum here: Town Car rear air suspension spring replacement

To replace the height sensor we have a procedure in our Tech forum here: Town Car air suspension height sensor replacement and adjustment that contains suspension height settings too.

Let us know if the system does not turn on the compressor, etc.
Thanks for the details! On the 2001 TC, I did find the old sensor switch a bit contorted, but it straightened out. I am using the one from the boneyard that looks in better shape. The air compressor does not naturally come on (although I "bench tested" it by applying 12V directly, and noticed that pressure was maintained up to solenoids). There are no error messages with system turned off. What is interesting is that steering is hard at low speed. I assumed this was the belt or belt tensioning pulley, as it seems looser than the 2003 belt tension. But as you mention that the module controls both, I have to explore that. Since the compressor does not activate in this bottomed out state, should I swap the module?
 

04TC

Junior Member
77
10
8
Tampa, FL
I think she has the premium stereo - first pic.
If it is the premium stereo, it could easily be a problem with the head unit itself. eBay has a couple of used ones for sale but they are expensive, usually $200+ dollars. I looked on replacementradios.com and they don't seem to have them.

I almost forgot that, if there is a stock subwoofer in the car then you almost certainly have the premium system. So that is a way to double check which sound system you have.
 

Town

Senior Member
4,400
133
63
Ottawa Ontario Canada
Thanks for the details! On the 2001 TC, I did find the old sensor switch a bit contorted, but it straightened out. I am using the one from the boneyard that looks in better shape. The air compressor does not naturally come on (although I "bench tested" it by applying 12V directly, and noticed that pressure was maintained up to solenoids). There are no error messages with system turned off. What is interesting is that steering is hard at low speed. I assumed this was the belt or belt tensioning pulley, as it seems looser than the 2003 belt tension. But as you mention that the module controls both, I have to explore that. Since the compressor does not activate in this bottomed out state, should I swap the module?
The default for the power steering if the module is not working is full power. So not sure why you are getting low pressure to the steering unless the pump is not working or the EVO system at the pump is stuck in low pressure position. The suspension module sounds problematic though since with the suspension switch off the module should send a message to the LCM to turn on the suspension warning message in the dash. You may want to check the wiring at the module or replace the module. The suspension switch is separate from the module power supply, it connects to a sensor that the module then determines if suspension should be made operational or disabled. Perhaps check the power supply fuse for the module.
 

dweiss

New member
20
3
3
I replaced the steering/suspension module with junkyard part from same (2001-2002). The suspension compressor still does not come on, and no message lights either. One surprising development is that the rough steering at low speed cleared up. I even verified by putting the old module back on and observing the rough steering come back. Wondering if the module sees that a condition is not being met (like doors closed, etc. even though there is no message to that effect)
______________________________
 

dweiss

New member
20
3
3
I did a lot of "pin out" troubleshooting and verified that I could raise the vehicle manually. It turned out to be the suspension module - so it's working now.
 

dweiss

New member
20
3
3
If it is the premium stereo, it could easily be a problem with the head unit itself. eBay has a couple of used ones for sale but they are expensive, usually $200+ dollars. I looked on replacementradios.com and they don't seem to have them.

I almost forgot that, if there is a stock subwoofer in the car then you almost certainly have the premium system. So that is a way to double check which sound system you have.
It is the premium. I've been looking around. The dash looks a bit more challenging! Thanks for all your posts!
 

dweiss

New member
20
3
3
The default for the power steering if the module is not working is full power. So not sure why you are getting low pressure to the steering unless the pump is not working or the EVO system at the pump is stuck in low pressure position. The suspension module sounds problematic though since with the suspension switch off the module should send a message to the LCM to turn on the suspension warning message in the dash. You may want to check the wiring at the module or replace the module. The suspension switch is separate from the module power supply, it connects to a sensor that the module then determines if suspension should be made operational or disabled. Perhaps check the power supply fuse for the module.
Still figuring out how to post here! The second EVO/suspension module resolved the issue. Quite a learning experience to go through connector pins and testing/activating systems one at a time. But that led to the conclusion that it could only be the module.
 

wimpy

Senior Member
179
6
18
Charlotte, NC
"I did a lot of "pin out" troubleshooting and verified that I could raise the vehicle manually. It turned out to be the suspension module - so it's working now. "

For us lesser enlightened folks, what is "pin out" troubleshooting? What procedure would I follow to raise the vehicle manually? Are there differences in the suspension modules from 99-2009?
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dweiss

New member
20
3
3
If you pick up a computer module (or its connector), you see a number of pins that fit the connector (or vice-versa) depending on which is male and female. But to troubleshoot circuits that are essentially "hidden away" in the module can seem daunting. A "pin out" diagram shows you what voltages and resistances to expect at each pin (using a volt-ohm meter), and with detailed instruction, how to bypass certain functions of the module. That way, if you get a manual response w/o the module, then it may mean the module is defective. My options were to take the car to a garage with a full scanner - that does exactly the same thing, much more efficiently. But it would have cost over $100. Or do it myself. I had a trial membership in a paid service where I could ask a mechanic to send me the diagrams so I could do it myself at a fraction of the cost (mostly just my time) and learn something in the process. I haven't researched the circuitry from 99-2009, but I imagine that whatever years use the same module would have the same pin outs. I know that 2003 is different than 2001 (and that 2002 shares the same module as 2001). The attachment gives an idea of what I used for the 2001.
 

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