Repairing the Starting System

(In the summer issue of Moss Motoring, we brought you part one of this informative treatise by Louis C. Belby. Many of you wrote and told us how much you appreciated this information, so it’s only fair that we now bring you part two.—Ed.)

Take another wire with alligator clips on each end (it doesn’t have to be as thick as a jumper cable), touching one end to the solenoid battery terminal (the bolt with all the wires) while you touch the other end to the spade connector attached to the brown/white wire. The solenoid should make a loud click as it kicks out the pinion gear, the starter motor should run, and the engine should crank but not start (that’s why you left it in neutral with the key off). If the starter motor checked out in the previous step but it doesn’t operate now, you have a bad solenoid. If you hear the loud click but the starter doesn’t run, the solenoid coil is good but the contacts are probably too dirty to pass current. In this case, you must remove the starter and solenoid from the car. (Again, disconnect the negative cable first at the battery!) At this point, you might want to consider contacting an automotive repair technician to help you diagnose your vehicle and work on a Vehicle Starter Repair.

First, remove all wires from the solenoid, noting their position. Unbolt the starter from the engine, remove the solenoid from the starter, take the two screws off the end cap, the two nuts off the bolt terminals, and unsolder the two connections on the end cap. Carefully pry off the solenoid end cap, noting which wires go to which of the connections you unsoldered, polish all the contacts inside the solenoid with emery cloth, and reassemble.

In case there is no click, the source of trouble could be a dirty solenoid plunger, which prevents it from retracting into the solenoid. This is why bashing a solenoid with a hammer sometimes renders it operative; you’ve temporarily freed it up, but this is definitely a short-term solution. In the case of a dirty plunger, remove it from the solenoid and polish both it and the inside of the solenoid with some emery cloth. If, after polishing the plunger and reassembling the solenoid, it still won’t work, your coil isn’t operating. Double check that you resoldered the coil connections tightly to the proper terminals on the solenoid end cap. If it still doesn’t work, you’ll need to replace the solenoid, which can be purchased separately from a starter. Before reinstalling the starter and solenoid on the car after repairing/replacing one or both, it would be a good idea to do a bench check, using either your own spare battery or by taking the unit to an auto store. This test is done just as it would be if the starter were on the car, but now you also have to ground the starter to the negative terminal of your battery since it isn’t grounded through the car.

If the starter motor and solenoid both check out, it’s time to inspect the starter switch. Get ahold of a friend and a voltmeter or test light. Disconnect the white/red wire from the W1 terminal on the starter relay under the hood, and attach the positive wire from your voltmeter or either lead from your test light to the wire (not the terminal), touch the negative voltmeter lead or the other test light wire to a good ground, and have your helper turn the ignition key all the way to start. If the voltmeter shows 12 volts or your test light illuminates, your starter switch is good. You know this because the ignition switch is sending current to the starter relay through the red/white wire. If, on the other hand, no current is detected, you must change your starter switch. This is readily accessible by removing the plastic covers over the steering column.

If the starter, solenoid, and ignition switch are functional, now check the starter relay. Attach your voltmeter positive lead or one test light wire to the C2 terminal (not the wire) with the brown/white wire attached to it. Connect the negative voltmeter lead or other test light wire to a good ground, have your helper turn the key to start again, and see if there’s current by looking at your voltmeter or test light. If so, the relay is good, since you know that the relay is passing current from the battery to the starter solenoid. If no current is indicated, you have a bad relay, a fairly common problem, and it must be repaired or replaced. A relay can be faulty for two reasons, and depending on the problem, it may be possible to repair it with the help of an auto repair shop. The cover can be pried off the relay, and the contacts between the C1 and C2 terminals, which might be too dirty to pass current, can be polished with emery cloth. If the relay coil itself attached to terminals W1 and W2 is inoperative, a loose connection can be soldered if this is the problem. Otherwise, replace the entire relay, which is fairly inexpensive.

If none of the above tests finds the source of your trouble, the problem might be in one of the wires mentioned above. Wires, however, tend not to be defective. Connections, though, can become loose or corroded, and all of them should be inspected while carrying out the above tests and cleaned, tightened, or replaced if necessary. If you decide to check your wires as a last resort, you must check each one for continuity using a test light or other appropriate instrument. I would bet, though, that you will have found the source of your problem long before reaching this point. Happy sleuthing!