1993 Cadillac EL Dorado 1993 Eldorado 4.9 electrical proble

IBJIMP

MEMBER
1993 CADILLAC ELDORADO
V8
FWD
AUTOMATIC
80,000 MILES

I have a great 93 Eldo with the 4.9. Recently I have been having problems. I began noticing the fuel gage was having false readings and this was only the beginning. After about a month of this I noticed that when I turned the key off and waited about 30 seconds the analog speedometer would start to bounce up and down. Then a few seconds after that with the key still off the digital instrument cluster would turn on. Then a few seconds more the heater/AC. Blower would turn on. Also the air ride pump will turn on and off normally. There are no engine codes being displayed. I diconnected the Heater/AC blower and found that if I wait until the digital cluster comes on after I turn off the car I can push the Display off button and it will stay off until I start the car again. Can anyone help me out? I have no idea whats up with the car.

1 Reply

FACTORYJACK

MECHANIC
4,159 POSTS

The erroneous fuel gauge readings may be unrelated, as level sensor faults are possible. The ELC compressor should only exhaust when the key is off, the compressor should not run. This is to accomodate a vehicle that is unloaded after parking. A vehicle that is loaded with the key off, will cause the compressor to activate at first ignition event. On the blower/ipc concerns, they are a bit bizarre. At first glance I would suspect a corrupt cluster, since it is having cluster issues, and the HVAC functions are requested from the cluster. You say there are no 'engine' codes, are there any codes? If it was checked with a code reader, it would just tell you engine codes. If you have not, run the diagnostics through the IPC by pressing off and warmer on the climate panel with the key on. After the segment check, it will display codes for all modules. Reply them to post. Another possibility would be to look for an IPC fuse, or disconnect the IPC, and at least see if the blower still turns on. Basically, a request is sent over the data line to the AC programmer, and it controls the speed of the blower. Take note of what speed the blower comes on at, when the key is off. Does it remain at the speed it was last shut down at, or does it ramp up to full speed?