Volvo Repair: 92 940, using jumper cables, voltage drop test


Question
QUESTION: when you turn key to start relay above battery and also under dash,click.Checked starter out of car. its ok. 12volts to starter lug, but on start mode small blade terminal on starter only shows 10 volts.any ideas

ANSWER:      John, nice job of gathering (testing) the important data for me to help you. Thank you! You should have battery voltage less no more than .5 volts on that pin when ignition is turned to start mode. 10 Volts is right on the border of engagement.

   A quick test would be to take a jumper wire and connect to battery +. Make sure the vehicle is NOT in gear. Set e-brake. Touch the jumper to the solenoid pin. If she turns over, your problem is in the blue wire circuit or the ignition switch. If it doesn't, I would look at ground issues. Do you know how to do a voltage drop test? It's a great way to test the cables.

Mark

---------- FOLLOW-UP ----------

QUESTION: thanks so much for your help,
I ran a jumper from batt. to small blade terminal.small sparks,next added ground wire to case of starter.same results.after cleaning all ground contacts,small blue wire has almost 12 v.when key is in start mode.Is it possible solenoid is causing this, will spin when out of car (using jumper cables) but nothing when installed.Im baffled.

Answer
  Now, now, now John. Don't be baffled, it's not magic or rocket science.VBG
  First, are you using the same battery when you are testing it with the jumper cables?
  Ok, there are only three things you have to have to make her spin. Battery ground, battery positive and starter pick (blue wire) You've tested and know you have pick. One at a time, take your jumper cable and go from battery + to the big post on the starter solenoid and try. If no go, remove that cable and connect a jumper cable from the battery - to the starter case. (usually the end bolts on the starter work good.) In both tests, wiggle the clamps to be SURE you have made a good connection. Let me know what the results are.

Mark