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sedan DeVille
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3 Posts
Discussion Starter #1
Bought a 91 sedan DeVille for my Daughter, all the main ingredients work fine, I am VERY impressed with the car, however, she demands more than I do.
I have looked around here a bit, learned some already, car has the 4.9 liter and 108,000 on it- if any more info is needed please let me know.
I pulled some codes, per this site, not near as easy as some others I own.
Codes said (I Think) Low refrigerant,TPS not reading correctly at closed throttle, LR suspension?, and several that looked like power loss.

What I know-
I have no blower motor in heat or cool, have unplugged the motor and checked for voltage, never gets any. The rear defrost does not work, dont know what to check. The radio does not work, never powers up, not sure what to check, the antenna never raises either. I suspect the auto-darkening mirror is not working, never had one before--- dont know what to check.
Fuses are good, have not checked any relays or modules yet, from what I have read here it MIGHT be a BCM... could one of those do all of that?
I did pressure the AC up to about 65 psi, still nothing and r-12 is not cheap- I have about 22lbs left and several cars that use it.
What I dont know-
A lot, thats why I am here.
TY
Owen
 

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White Diamond '03 DHS (with DTS floor shift)
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87,094 Posts
Low A/C code disables the compressor to save it. You need to clear that code to enable it before recharging it.

Closed throttle switch just might need the contacts cleaned.

Sounds like the radio might not be getting any power.

Suspect the blower motor is dead and needs to be replaced.

Not sure what to tell you about the mirror.
 

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1990 350 Brougham (The cruiser), 1988 Mark VII LSC (The DD)
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5,545 Posts
If the blower motor never gets voltage and the rear defroster doesn't work I would say you need a new climate control center.

There is no relay for the radio, the relay is internal. Go on Ebay and buy a factory service manual (got mine for about $20). They are loaded with information and are well worth the money. The way to check for power would be to pull the radio out and using a wiring diagram, check the signal voltage to the radio (comes from the ignition switch).
 

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1992 Sedan Deville, 1984 Lincoln Town Car
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759 Posts
There are three types of fuse 1) I/P fuses, 2) relay center fuses and 3) Maxi fuses, did you check all of those? If not, check the Maxi's two banks -LH and RH. Blower motor is Mfuse #3 in the RH fuse block (driver side view, so it's on your left when facing it from the front looking back) There is probably a long black plastic cover housing the maxis and the UH relays that you will have to remove for access. Let me know. the ECC Power Module is next to check.

Radio actually does have a relay called RAP (Retained Accessory Power) but if your Windshield wipers are working that relay is okay. More on that with wiring info for you.

Please post the exact Code #'s you got from the OBD. It would help me t-shoot for you.

Thanks
 

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sedan DeVille
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3 Posts
Discussion Starter #5
Wipers do work.
Pulled codes per the sticky on this site- using the info center, strange codes to me but will run again and post later today.
I have checked fuses on the driver side pulldown box and 2 boxes under the hood with Maxi-fuses. Are there more with the relays? have not yet looked there, passenger side under the dash right?
I need a book or two, will have one soon but untill then this forum is all I have.
How do I clear the code for A/C?

Thanks all,
Owen
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
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87,094 Posts
Once in the diagnostic mode HIGH FAN = YES and LOW FAN = NO to the prompts after the DTC's have been displayed. Answer no until you see CLEAR CODES?
 

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1992 Sedan Deville, 1984 Lincoln Town Car
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759 Posts
The RELAY CENTER has eight more fuses one of which is the blower motor fuse and the heated mirror fuse. Also, there are 10 relay positions only 8 or 9 relays tho' depending upon your chassis style. If you have a Commercial Chassis Series (CZ) the antenna relay is there, if not it is located in the trunk on the antenna motor assembly. One of those relays is also the Amplifier relay for the radio.

Location = behind the glove compartment. You need to remove the lower insulator/ sound panel of the dash and the glove compartment for access. You'll see it on the far RH side once the GC is removed.. The BCM is also there, big silver box with 2 big connectors along the RH side of it (just in case more testing is needed) More later.
 

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sedan DeVille
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3 Posts
Discussion Starter #8
E55 is the only one that came back
I have A/C compressor now but still no blower, never gets voltage.
Will get behind the glove box tomorrow evening.
BTW- not really sure how I finally got the codes cleared, seems the fan buttons were toggling and the off button either by itself or with a fan button was clearing, I never saw "clear codes".
Thanks for the help, I am sure I am not quite finished.
 
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