I have an 87 Signature Town Car that has its fair share of electrical issues. The digital fuel gauge jumps all over the place. The message center occasionally dims. Cruise sometimes resumes when using the turn signal or flashing high beams. I had hoped doing the 3g alternator upgrade might fix some of these problems, but one month later they persist. Two issues that I'm currently interested in pursuing are as follows:
1) The keyless entry keypad is mostly working except for the trunk release and drivers door unlock. When entering the five digit code nothing happens until I hit 3/4 and all doors unlock, including the drivers door. But entering the code alone won't just unlock the drivers door. (This initially had me thinking I had the wrong code when I bought the car. I ended up making a list of every possible code and entering them with my brother - to no avail. It was only a week later when I thought to try unlocking all doors that I discovered the code printed on the module behind the glove box was correct all along.)
Similarly, entering the code and hitting 5/6 won't pop the trunk. The soft-close motor is broken and has been unplugged, but the button in the glove box will still release the lid.
All five keypad buttons light up when pressed and can be used for entering codes. And both the drivers lock and trunk release work through other means, so I feel like I should be able to rule out component failure at both ends. But never having done electrical work before, I'm not sure where to begin troubleshooting this.
2) Both opera lights and the rear reading lamps occasionally get very dim. I haven't nailed down anything that might cause it to dim or bring it back. I just occasionally notice the opera lamps not lit when looking in the mirror or see the reading lamps just barely on when getting in or out. The problem seems to happen whether the car is off or on. I did replace all four bulbs with LEDs some time ago, though I didn't have the car long enough at that point to say whether the problem preceded that project or not. I've also replaced most other bulbs with the same LEDs and haven't noticed an issue on any other circuit.
From searching through other threads it seems that some interior lights ground through screws or bolts which can come loose over time. But between these four bulbs, the opera lights must ground directly into the body and the brackets holding the reading lamps are fastened back onto the vinyl/plastic interior panel. Is there another ground somewhere that could've come loose?
1) The keyless entry keypad is mostly working except for the trunk release and drivers door unlock. When entering the five digit code nothing happens until I hit 3/4 and all doors unlock, including the drivers door. But entering the code alone won't just unlock the drivers door. (This initially had me thinking I had the wrong code when I bought the car. I ended up making a list of every possible code and entering them with my brother - to no avail. It was only a week later when I thought to try unlocking all doors that I discovered the code printed on the module behind the glove box was correct all along.)
Similarly, entering the code and hitting 5/6 won't pop the trunk. The soft-close motor is broken and has been unplugged, but the button in the glove box will still release the lid.
All five keypad buttons light up when pressed and can be used for entering codes. And both the drivers lock and trunk release work through other means, so I feel like I should be able to rule out component failure at both ends. But never having done electrical work before, I'm not sure where to begin troubleshooting this.
2) Both opera lights and the rear reading lamps occasionally get very dim. I haven't nailed down anything that might cause it to dim or bring it back. I just occasionally notice the opera lamps not lit when looking in the mirror or see the reading lamps just barely on when getting in or out. The problem seems to happen whether the car is off or on. I did replace all four bulbs with LEDs some time ago, though I didn't have the car long enough at that point to say whether the problem preceded that project or not. I've also replaced most other bulbs with the same LEDs and haven't noticed an issue on any other circuit.
From searching through other threads it seems that some interior lights ground through screws or bolts which can come loose over time. But between these four bulbs, the opera lights must ground directly into the body and the brackets holding the reading lamps are fastened back onto the vinyl/plastic interior panel. Is there another ground somewhere that could've come loose?
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