1978 Cadillac Eldorado - defective door jamb switch repair.
I´m fully detailing the 78 Biarritz at the moment. During this I think I found the only non working gadget this car offers. The 78 Biarritz came with an automatic seat back release. When you open the door a solenoid engages and you can fold the seat back without pushing any button or lever to allow rear passengers to get in or out of the car. When you close the door again the seat lock engages and the seat back stays in position.
I also have the same system on my 1971 Lincoln Mark III where I had some problems as well in the past with a loose wire.
On the Biarritz the passenger side worked flawlessly, but on the drivers side the solenoid would not engage.
I started my search for the problem at the top of the two door jamb switches which is the one controlling this function.
When I wiggled it and pulled it out, I could hear the solenoid engage. So I knew that the problem must be with this switch.
Unfortunately it's not easily accessible. As I do not have the 1978 shop manual yet - it took me a while to figure out how to access it.
I managed to get to it through the lower dash and to uninstall it.
As it turned out it was slightly bent and did not make good contact once the door was opened.
I carefully bent it back straight - and after some trial and error it was back in working order.
It took me a good hour to fix this.
Now I´m back to cleaning the car to my standards, something that will probably take the whole winter...
The upper switch is controlling the seat back solenoid. (Picture was taken before cleaning the door jambs...)
The removed door jamb switch. When the door is closed no contact is made and the solenoids are not energized causing the seat back to be locked in position.
You can see that the switch was slightly bent - making no good contact.
When the door is open contact should be made and the solenoid should energize... The switch did no longer make a good contact though.
I had to remove the lower dash to access the cables on the rear of the door jamb switch through a tiny hole and disconnect the connector with a long nose plier...
I´m now in the long process of thoroughly cleaning the engine bay to look like new again...