Trunk Opener Circuit

[mighty7]

I have had a spider for 28 years now and I finally got the trunk opener to work. One goofy thing about it is that the engine has to be running. Is it just me or is that a goofy way to wire up the relay that powers open the trunk opener solenoid? As you can see the ground for the relay goes through an oil pressure switch that doesn't close unless the car is running. I can get it to work without needing the engine running by just grounding directly pin 86 on the relay. Has anyone else done that? Anyone know why it is set up to need the engine running?

[bobplyler]

Mine never had a trunk opener (other than the key).

[GeorgeT]

You can route the grey wire at C44 or C29 directly to ground rather than through the Oil Pressure Switch.

[mighty7]

Is that the only purpose for the oil pressure switch is to allow the trunk to open? Or is it used elsewhere? Seems silly to me.

[wikkid]

Do Pininfarinas have this switch/solenoid setup?

[spider2081]

I think the oil switch is only closed when the oil pressure is low or when the engine is not running. That is when the oil pressure light is lit. The schematic is showing you the trunk can not be opened if the engine is running. This prevents accidentally opening trunk when car is in motion

[mighty7]

Thanks spider2081. That actually makes sense. Where in the car is the oil pressure switch located, because my car wouldn't open while off, so I suspect my switch might be bad or missing? Can you or anyone upload a picture of the location?

Yes wikkid, the Pininfarinas do have the trunk release feature. In fact that schematic is from the 1983-85 Pininfarina wiring diagrams. I am re-drawing the wiring diagrams, adding color so I can trace by component and not just by sub-system.

[spider2081]

On my 81 Spider the oil pressure switch is located on the oil filter housing. I can see it by looking down near alternator on the drivers side.
A Good troubleshooting procedure is to begin in the middle of a circuit. I would make my tests first at the relay. See if you have power and ground there.
If your low oil pressure light works I would assume the oil pressure switch is good. Although I don't know if your car has 2 oil pressure switches one for the light and one for the trunk.

[mighty7]

Thanks again for everyone's help. I did indeed have a broken oil pressure switch. I replaced it and now my trunk opens from a simple push of a button on the dashboard. I can't believe I have had that silly solenoid in my trunk for 18 years and didn't even know about it. I just assumed it was missing.

[davery]

Wouldn't this be a security issue? If you could release the trunk without a key, then someone could slice your top and get into the trunk.

[spider2081]

I believe the ignition switch needs to be in the "start" or "run" positions for the trunk solenoid to have power. Fuses 11&12 are power window fuses that receive power from the poser window relay once the ignition switch is turned on.