drewpster
Commander
- Joined
- Oct 17, 2006
- Messages
- 2,059
Re: solenoid
A starter solenoid is basically a remote operated switch. When the key is turned to start, it tells the solenoid switch to turn on. This allows current from the battery to flow to the starter turning it and starting the engine.
The key switch part of the solenoid is the two small posts. One of the wires comes from the key switch. It should only get hot when the key is turned to "start".
The other small post is a ground. It should be connected to a ground point, the engine block, or anyplace there is a ground to the battery. Most likely it is connected to the engine block close by the solenoid.
The two big wires on the solenoid are both hot wires. One should come directly from the hot side of the battery to a big post on the solenoid. The other big post should connect directly to the starter.
Again, when the key is turned to "start" the small posts energize the solenoid closing it. (click sound) This energizes the starter and it should turn.
Connect your test meter's ground (black) to a ground on the engine block. (not the solenoid) Set the meter like Silvertip's picture. Touch the meter's positive test lead (red) to each big post on the solenoid. It should read battery voltage on one post (no less than 12 volts), and no volts on the other solenoid post. The big post that shows voltage is the one that goes to the battery. If it shows less than 12 volts on the solenoid/ battery post, there is a problem between the battery and the solenoid. (bad cable, bad connections, dead battery)
Assuming all that is good, go to the next step.
Now check the key switch side of the solenoid. Leave the meter as it is. Have someone turn the key to start and you should hear a click. With the key held on "start" touch the meter's red test lead to each small post. (do this only for a short period, get help to turn the switch) One small post should read battery voltage and the other nothing.
(you should also get battery voltage on both big posts)
If you get voltage on both small posts with the key on "start" then the solenoid is bad. If you don’t' get voltage on Both BIG posts with the key to "start" than the solenoid is bad.
If you do not get voltage at all, on the small posts, than the problem is between the solenoid and the key or the fuse panel.
If you have good voltage at one big post with the key off.
If you have good voltage at one small post and BOTH BIG posts with the key switch to "start" than the solenoid and all the connections are good.
All your meter readings should be within .2 volts of each other and battery voltage. Make sure your battery is charged and check it's voltage with the meter at the battery before beginning. (now go back and check again)
Now, if all that shows good, then turn the key to "start' again and check voltage at the starter post. If the starter has good battery voltage, and it does not turn, than the starter is fried. If the starter's ground is good.
Why now you ask? Because most starter problems are not starters, they are normally related to something else in the circuit. It is better to begin any starter problems diagnosis by checking the battery and all the cable and wire connections before beginning. The problem is far more likely to be found there.
A starter solenoid is basically a remote operated switch. When the key is turned to start, it tells the solenoid switch to turn on. This allows current from the battery to flow to the starter turning it and starting the engine.
The key switch part of the solenoid is the two small posts. One of the wires comes from the key switch. It should only get hot when the key is turned to "start".
The other small post is a ground. It should be connected to a ground point, the engine block, or anyplace there is a ground to the battery. Most likely it is connected to the engine block close by the solenoid.
The two big wires on the solenoid are both hot wires. One should come directly from the hot side of the battery to a big post on the solenoid. The other big post should connect directly to the starter.
Again, when the key is turned to "start" the small posts energize the solenoid closing it. (click sound) This energizes the starter and it should turn.
Connect your test meter's ground (black) to a ground on the engine block. (not the solenoid) Set the meter like Silvertip's picture. Touch the meter's positive test lead (red) to each big post on the solenoid. It should read battery voltage on one post (no less than 12 volts), and no volts on the other solenoid post. The big post that shows voltage is the one that goes to the battery. If it shows less than 12 volts on the solenoid/ battery post, there is a problem between the battery and the solenoid. (bad cable, bad connections, dead battery)
Assuming all that is good, go to the next step.
Now check the key switch side of the solenoid. Leave the meter as it is. Have someone turn the key to start and you should hear a click. With the key held on "start" touch the meter's red test lead to each small post. (do this only for a short period, get help to turn the switch) One small post should read battery voltage and the other nothing.
(you should also get battery voltage on both big posts)
If you get voltage on both small posts with the key on "start" then the solenoid is bad. If you don’t' get voltage on Both BIG posts with the key to "start" than the solenoid is bad.
If you do not get voltage at all, on the small posts, than the problem is between the solenoid and the key or the fuse panel.
If you have good voltage at one big post with the key off.
If you have good voltage at one small post and BOTH BIG posts with the key switch to "start" than the solenoid and all the connections are good.
All your meter readings should be within .2 volts of each other and battery voltage. Make sure your battery is charged and check it's voltage with the meter at the battery before beginning. (now go back and check again)
Now, if all that shows good, then turn the key to "start' again and check voltage at the starter post. If the starter has good battery voltage, and it does not turn, than the starter is fried. If the starter's ground is good.
Why now you ask? Because most starter problems are not starters, they are normally related to something else in the circuit. It is better to begin any starter problems diagnosis by checking the battery and all the cable and wire connections before beginning. The problem is far more likely to be found there.
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