solenoid puzzle

[formariz 11,912]

I have the original solenoid on my 61 suburban, but occasionally it malfunctions by either not switching until I tap it with a wrench or it decides to switch on its own while in the shed. Tried to replace it with other solenoids but regardless of which one I used, the key switch will not activate it.When I bypass switch and power the switch terminal on the new solenoids they all work. My switch seems to be fine since it always works with the old solenoid. Any thoughts???? :thumbs2:

[TT-(Moderator) 1,129]

This one's easy, Cas.....

The OEM metal-cased solenoids (550/551/701, etc) were internally fed power from the battery cable connection and required the trigger post to be GROUNDED to complete the electromagnetic coil circuit.

Newer solenoids are grounded through the mounting bracket and require battery voltage (power) through the trigger post to energize the coil.

[formariz 11,912]

I understand now. However does it mean that I need a different switch? I played around a little bit with the unused third terminal on the switch only to have it smoke! Any possibilities of obtaining a similar solenoid? :thumbs2:

[TT-(Moderator) 1,129]

If your ignition switch smoked but is not smoked , you can actually use a Bosch relay to trigger a "modern" solenoid.

By wiring the relay so it needs grounded to activate it's coil while using the switched terminals to supply power to the starter solenoid, you can retain your original switch.

[formariz 11,912]

:thumbs: Luckily not smoked yet. That would really upset me since I want to keep the original with the split key.Thank you very much. Very simple to resolve then. :ychain: