01 LS A/C, Electrical and Brake Problem !!

hi everyone, yes im a newbee:runaround: . I have a few problems with my Ls and was wondering if anyone can help. I bought this car over a year ago started having problems with it once I hit over 100,000miles. It currently has 110,000miles. First off, my ac does not work. I press the ac button and it lights up but does not turn on. I check if power was running the the clutch when the ac button was lite and there was no power. I then checked it at the relay and still no power. If I put direct power onto my clutch, Bamm, It WORKS! if i put direct power onto 3-6 times real fast and remove the direct power my ac will stay on for an hour or so, any ideas any one??? I know it cant be the compressor because I dont even get power at the relay. I was thinking it had to do something with the PCM. Another reason I think it is the pcm is because 2-3 times since i bought the car I would be driving and the ATC would say it was not on when it was on. Also twice when I went to the store I unlocked the car to get back in, tryed to turn it on and would not click over. It was as if there was a kill switch. but after 10-15 doing nothing in the car, I would try it again and it would work.... I also have a problem with my brakes, whenever i brake hard, i hear about 4-5 "clicking" noises from my front end, any ideas??? I love this car but so many problems. Thanks in advance everyone

Welcome to the forum!

I'm not sure that any of your "problems" are really problems. Your AC issue sounds like it could just be due to a low charge of refrigerant. However, if you ran the compressor for an hour with a low charge, you may have damaged the compressor. The refrigerant carries the oil to lubricate the system. If it's low and the pressure switches did their job and disabled the clutch, that would explain it not engaging. When you forced the clutch to engage, did you check to see if the air from the vents was getting cold? Have you had gauges connected to the system to check the pressures?

I'm not sure what you are referring to by ATC. Are you referring to the traction control?

The clicking when using the brakes hard may have just been the ABS kicking in. We'd need a better description before really saying it's normal or a problem.

-Rod

hi Thanks for the quick response Rod. the a/c is fully charged and the pressures are right I took it to an AC shop. It has to do with something electrical or sensor because there is no power to the a/c relay. Oh by ATC i do mean traction control. Is the clicking normal when I brake? Thanks

I just did the DATC self test and I got code 19 46. any idea anyone? I searched the site but ended up empty handed. Thanks

Interesting. According to the factory service manual, code 1946 means "Evaporator discharge temperature sensor open circuit." The reason I say this is because that same sensor went out in my wife's 2002 LS. On hers it didn't go open circuit. I searched the Internet and couldn't find any instances of others failing. When I ordered it from the dealer, they said they had never ordered one before (and I see all kinds of LS's on the roads around here). But, just weeks after replacing the one in my wife's car, another person on this forum found theirs to be bad, and yours is giving a code for either an open sensor or a wiring issue for the sensor.

For details, try searching the forum for keywords "discharge sensor" and you'll be in for some interesting reading.

For the other person that found their sensor to be faulty, see this thread (http://www.automotiveforums.com/vbulletin/showthread.php?t=757235&page=4&highlight=discharge+sensor).

-Rod

Thanks Rod. Thats some great info and I am going to look it up right now. Do you have any idea on how I can get my hads on a factory manual for my 01 LS 3.9L engine.?

so should i replace the sensor? where is it located at? How can I test it to see if it is faulty? is that the reason why I am getting no power to the relay for the clutch to engage? i know those are a lot of questions but I really need your help thanks.

Ahhh, I forgot about the compressor not engaging. I'll have to look over the manual a bit more this evening.

I wouldn't start with replacing the sensor. As I mentioned, the problem could also be in the wiring to the sensor. Since the code implies there is an open circuit condition, if you're lucky it's not an intermittant and therefore you can easily check the sensor for open. Remove the sensor and use an ohm meter to measure between the two terminals. At 50-68 degrees F the sensor resistances should be between 37k and 58k ohms. At 68-86 F = 24k - 37k ohms, and 86-104 F = 16k-24k ohms.

You can get the factory service manual information from Alldatadiy.com. There is an annual subscription fee, but the information provided is from the factory service manual plus you get full TSB and recall information.

-Rod

Hi Rod, I took the advice you gave others (change the sensor with the pass. discharge sensor) and I reran the self test and now when it counts down all the way to 0, instead of giving me a code, the whole scren lights up. I think it might be the sensor. I did the Ohm test and I got 36, in 64degrees. Anyother advice?

Based on the cost of the part and the fact that is is definitely bad (assuming that's 36 ohms and not 36 kohms) I'd start there. If that fixes everything, great. If not, it was not wasted money.

The AC clutch relay is controlled by the PCM.

-Rod

Great News Rob.. IT WORKED!! I replaced the sensor and got no more codes when I did the self test. I tried to turn the ac on and still the clutch did not engage. I was about to give to up and thought to check out the fuses before, and the ac clutch fuse was apparently blown again. (I replaced it about a month ago when I was trying to fix this ac problem). I tried it once more and BAMM. It worked! ..apparently the discharge sensor wont let the clutch engage if the sensor is no good. Thanks Rob, your living factory manual lol

next is my valve cover gaskets. does anyone know of a step by step site on how to do it?

here is a great link for step by step valve cover gasket repair for an 01 lincoln ls .

http://www.lincolnvscadillac.com/tech/Lincoln-LS/Valve_Cover_Seal_Inspection/Valve-Cover-Seal.htm

rod, i replaced all 3 sensors , ac clutch will not engage even when charge put to suction side , cant find pressure switch, and now getting 19 46 code. ? love car but now relay thinking about getting rid of it. constant problems

B1946 = Evaporator Discharge Temperature Sensor Open Circuit

Sensor, wiring, or DATC module. If your LS is 2003 to 2006, I have the troubleshooting details for this issue.

2000 v-6 ls, please send if you have it

2000 v-6 ls, please send if you have it

All I have is gen II. However, it may be pretty much the same on this. Here it is.

http://deneau.info/ls/s6x~us~en~file=s6xc0003.htm~gen~ref.htm#PS2-E