How do you know if a starter relay switch is bad?

Answer 1

Take it to a mechanic to test the battery, charging system, and starting system (both the solenoid and starter if they are separate pieces). Or remove the starter and take it to a parts store to have it tested. If the battery is ok, the alternator/charger system is putting out power, and you think the starter or solenoid is still the cause, unhook the ground from the battery post after the car has been running but is turned off and leave it like that till the next time you turn on the car when you'll screw it back on. If it starts no problem then it's probable it's the starter or solenoid that was sucking the battery dry.

Answer 2

First, the solenoid is powered by the battery. It will engage the bendix drive that turns the starter gear. If you just here a lot of click, click, click, then chances are the solenoid has to be replaced, and on certain models just taken apart and cleaned. Since I do not know what model engine, Of course this would help, then first make sure that the battery has charge. Run a volt meter across the battery, has to have more than 12.2 volts. Check all connections, and cables. And if you still have a problem, then the type of car in question would help.

Quick starter/solenoid checks all light vehicles.Some vehicles will only crank if the brake or the clutch pedal is pressed. Most modern vehicles have an engine immobilizer built into the ignition lock which can only be deactivated by a chip built into the ignition key. Automatics need to be in park or neutral. The engine ground, a thick braided electrical cable, should be securely fastened between the engine and the vehicle bodywork/ negative side of the battery. Check all engine compartment grounds for security. Some vehicles use a fuse or fused cable to carry heavy cranking current from the battery to the solenoid/starter. Excessive cranking of diesel engines (check your glow plugs!) will kill a starter motor very quickly.

There are two types of starter motor. Bendix type (separate solenoid), where the action of the motor spinning up 'throws' the bendix gear into the starter gear. Pre-engaged (solenoid mounted on starter motor), where the bendix is put into and out of the starter gear by a fork off the solenoid.

If the solenoid clicks when the ignition key is turned, try giving the back of the starter a smart tap with a rubber mallet, taking care not to damage any wires/connectors. If the engine then cranks, the chances are that the motor brushes are worn and need replacement. That, unfortunately, tends to be a specialist job these days (fused or crimped aluminum connectors), so a refurbished exchange unit from an auto electrics outlet is probably a cheaper option than a new unit. Vehicle breaker's yards are always a good source for spares.

Assuming a fully charged battery (12v approx) for all tests. {These tests will work just as well on a 6v or 24v system, using the appropriate meter range and/or lamp}. Just switching the ignition on can take 2 volts off the top of a battery. Don't worry, the electrics are designed around the drop.

To prove a solenoid, there are 2 big connectors and a small one. Do not disconnect anything. With a meter or a lamp connected between the small connector and ground (vehicle body). When you turn the ignition key to the start position the lamp should light/ the meter should read 12 volts. If nothing happens: if the car has an auto transmission, check the park/neutral switch then check for a fuse or ignition switch fault.

Assuming you got 12 volts or the lamp lit at the small connector, Meter/ lamp test between the big solenoid connector that is connected to the battery and ground, there should be battery voltage. Now connect the lamp or meter across the two big terminals on the solenoid making sure you don't ground them (sparks will fly!). The meter should read 12 volts/ the lamp should light. Turning the ignition key to the start position should reduce the voltage to zero/ the lamp should extinguish. If the voltage remains/lamp stays lit, the solenoid is in need of service/replacement. Same terms as before. It is better to change a pre-engaged starter as a complete unit if necessary. Where a solenoid is separate it can be changed on its own.

It is worth noting that starter motor brushes are more likely to fail than solenoids. Remote solenoids are more prone to failure than pre-engaged solenoids. Cleaning and dressing the heavy contacts inside a solenoid, when you can get at them, and making sure the armature moves freely, often cures the problem.

Answer 3

Good battery, good connections, starter will not engage, sometimes there will be a click, but not necessarily, if you can jump a wire over the solenoid terminals to the starter and start the engine it's a for sure thing.

Answer 4

An easy way to test a relay is to take a relay from a different system like headlights and switch them. If the relay is bad then now your headlights wont work but your car will start.

Any solenoid is an electrical switch with main terminals to pass current when operated by the small terminal being given a voltage.

To check if the SOL is faulty, bridge the two main terminals with thick jump lead. If the starter works the SOL is faulty.

If it still does not work check these with and without operating the key switch.

1.Good Battery voltage across battery terminals

2.Same voltage at starter

1 and 2 should be the same

if 1 and 2 check out ok you will most likey find the brushes in the starter motor have worn out.

Answer 5

If it is the solenoid just take a small jumper wire and jump out the two small terminals on the front of the solenoid and the starter should try to start the engine. If nothing happens then it is bad. Or you could take a volt meter and go from ground to the starter side of the solenoid and get some one to take the key and try to start it ,if you get 12volts and the starter doesn't try to engage then your starter is bad ,if you don't get 12volts then your solenoid is bad.

Answer 6

take the cover off the solenoid put a screw driver across the 2 studs crank the engine if it starts your solenoid was bad