checking pnp switch pins 6 & 7 and pins 5 & 9

[danton]

96 volvo 850 base that does not start. Replaced battery, starter & rebuilt ABS about a month ago. Runnning fine until tried to start in mall parking lot. Did not spin starter or start. Put in Neutral and started. Drove home and did not start. Raked shifter, pushed into park and started. Turned off and has not started since. Shorted positive battery to solenoid and it spins starter but does not engage to crank. Went and got another PNP from nearby yard. Rotated this switch and noted short between pins 6 & 7 twice, in what seems to be locations for park and neutral, and short on pins 5 & 9 when in approximate reverse position. Circuit diagrams show pins 6 & 7 on the pnp as the ones in the starter circuit and 5 & 9 for reverse lights. Took electrical connector apart on my car and noted the same short conditions on respective pins as transmission was shifted from park to reverse to neutral. Does this seem to indicate that the pnp switch is good? Thanks for any insight.

[jimmy57]

You have Identified the pins but ohm-meter checks may pass when current through the contacts fails. The "switches" are copper pieces with ballpoint pin springs pushing those copper strips against copper segments on fixed part of the assembly. The fixed segments can get hot and move down or the moving strips can simply wear and the contacts arc a bit and will not handle enough power to get the starter solenoid to engage.
The starter spins with no engagement to flywheel if you go big lug to big lug on solenoid at starter. You have to jumper between large lug where battery cable attaches to the plug on flat blade terminal to get the solenoid to move pinion into flywheel and also run starter motor to crank over engine.

[danton]

Thanks Jimmy57, will try in AM. Solenoid has what appears to be 3 connection points. Looking at back of it I see thick red cable on stud with nut on lower right, stud with nut on lower left with smaller cable, and a spade recepticle with no cable on top. When I short battery plus to lower left I get spinning no pinion. So are you saying to short lower left to top? Thanks again and still a little puzzled as to how a low voltage ohmmeter would read 0 and not let current flow, but I will change the PNP and see what happens.

[jimmy57]

The spade is the solenoid activating circuit. Are there two spades? The wire is green with blue stripe I believe. The solenoid will have the battery cable at 3 o'clock, starter motor cable out of solenoid is a 9 o'clock and the spade for starter activation is at 6 o'clock

You can have a 30 gauge thin speaker wire hooked between battery neg post and the engine as ground wire and an ohmmeter will read 0 ohms but that wire will not carry current that will operate starter. The contacts can be making a connection but you could have a distorted conductor in PNP sw. The ohmmeter shows 0 ohms but when you actually supply current the faint connection inside arcs and the circuit connection is lost. Ohmmeter readings have caused me untold wasted hours of work.

[danton]

Thanks again for your info. Went out and loosened the nut on the solenoid where the battery pos is connected and retightened trying to see where any other wires were connected and now it starts. Guess I need to clean those connectors on the cable ends since the new starter was installed.