safety switch ohms out, but bad voltage readings

rigoletto

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People,

continuing with my no start problem, I narrowwed it down to the safety switch- the one immediately below the big blade control lever (not the clutch one). When out, the switch ohms out at about 0.7 ohms on each of the 2 blade terminals (one with button depressed, and the other 2 terminals with button relaxed). When multimeter is on the BEEP mode with no ohms measured I do get the BEEP.

But when I snap back on the switch to the wire harness cluster, and depress the button by hand whilst measuring voltage to orange/white wire going to the solenoid, erratic voltage (between 7-9 volts). Continuity on thet O/W wire is good. Why do I get these low voltage results when the switch ohmed out?

Big thanks, people.
 

reynoldston

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You need amperage not voltage readings.
 

Rivets

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I feel you need to go back to the beginning. Here is a procedure to help pinpoint the cause of your problem. Start by making sure your battery is fully charged, then start the procedure. Go slow and don't assume any part, wire or connection is good. When you report back with results, we will have a better understanding what you are dealing with. Remember we can't see your unit or how the meter reacts, so you have to give us a picture with you desciption what is happening.



Electrical problems can be very easy or very difficult, depending on four things.
1. * How well you understand basic electricity.
2. *What tools you have and know how to use.
3. *How well you follow directions.
4. *You don't overlook or assume anything and verify everything.

Remember we cannot see what you are doing. *You are our eyes, ears and fingers in solving this problem. *You must be as accurate as you can when you report back. *The two basic tools we will ask you to use are a test light and a multi-meter. *If you have an assistant when going through these tests it would be very helpful. *These steps work the best when done in order, so please don't jump around. *Now let's solve this problem.

First, check the fuse(s), check battery connections for corrosion (clean if necessary) and *voltage - above 12.5 volts should be good.*

Second, check for power from the battery to one of the large terminals on the solenoid. *One of the wires is connected directly to the battery and has power all the time so one of the large terminals should light a test light or show 12 volts on a meter at all times.*

Third, *check for power at the small terminal of the solenoid while depressing the clutch/brake pedal and holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). If your solenoid is a four wire solenoid, check both small wire terminals as one is ground and the other is power from the ignition switch. *If your solenoid is a three wire solenoid, make sure the solenoid body is not corroded where it bolts to the chassis of the mower as this is your ground path back to the battery. *If in doubt, remove the solenoid and clean the mounting area down to bare metal. *If there is no power to the small terminal then your problem is most likely a safety switch, ignition switch or in the wiring.*

Fourth, check for power on the other large terminal of the solenoid while holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). *If you have power what is the voltage?

Fifth, check for power at the starter while holding the key in the start position (assistant again). *If you have power what is the voltage?

Sixth, check your ground circuit back to the battery.

After you have gone through each of the above steps, let us know what happened when you did each step. *At that point we will have great info to tell you how to proceed. *Remember you are our eyes, ears, and fingers, so please be as accurate as possible.

Be as specific as possible with voltage readings as this will help diagnose your problem quicker. *If you do not know how to perform the above checks, just ask and I will try to guide you through it. *Youtube also has some videos and as you know a picture is worth a thousand words.
 

rigoletto

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Joined
Jan 8, 2012
Threads
37
Messages
287
I feel you need to go back to the beginning. Here is a procedure to help pinpoint the cause of your problem. Start by making sure your battery is fully charged, then start the procedure. Go slow and don't assume any part, wire or connection is good. When you report back with results, we will have a better understanding what you are dealing with. Remember we can't see your unit or how the meter reacts, so you have to give us a picture with you desciption what is happening.



Electrical problems can be very easy or very difficult, depending on four things.
1. * How well you understand basic electricity.
2. *What tools you have and know how to use.
3. *How well you follow directions.
4. *You don't overlook or assume anything and verify everything.

Remember we cannot see what you are doing. *You are our eyes, ears and fingers in solving this problem. *You must be as accurate as you can when you report back. *The two basic tools we will ask you to use are a test light and a multi-meter. *If you have an assistant when going through these tests it would be very helpful. *These steps work the best when done in order, so please don't jump around. *Now let's solve this problem.

First, check the fuse(s), check battery connections for corrosion (clean if necessary) and *voltage - above 12.5 volts should be good.*

Second, check for power from the battery to one of the large terminals on the solenoid. *One of the wires is connected directly to the battery and has power all the time so one of the large terminals should light a test light or show 12 volts on a meter at all times.*

Third, *check for power at the small terminal of the solenoid while depressing the clutch/brake pedal and holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). If your solenoid is a four wire solenoid, check both small wire terminals as one is ground and the other is power from the ignition switch. *If your solenoid is a three wire solenoid, make sure the solenoid body is not corroded where it bolts to the chassis of the mower as this is your ground path back to the battery. *If in doubt, remove the solenoid and clean the mounting area down to bare metal. *If there is no power to the small terminal then your problem is most likely a safety switch, ignition switch or in the wiring.*

Fourth, check for power on the other large terminal of the solenoid while holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). *If you have power what is the voltage?

Fifth, check for power at the starter while holding the key in the start position (assistant again). *If you have power what is the voltage?

Sixth, check your ground circuit back to the battery.

After you have gone through each of the above steps, let us know what happened when you did each step. *At that point we will have great info to tell you how to proceed. *Remember you are our eyes, ears, and fingers, so please be as accurate as possible.

Be as specific as possible with voltage readings as this will help diagnose your problem quicker. *If you do not know how to perform the above checks, just ask and I will try to guide you through it. *Youtube also has some videos and as you know a picture is worth a thousand words.

OK, all good points, but I did all that- meaning did all the above checks. results- batt has 12.66v. Recently deep charged, and held. It actually did start the mower one time before i started having the problem.

2) solenoid does have voltage to one big wire.

3) no power at smal terminal of solenoid. removed/cleaned/no rust, leading one now to suspect safety.starter as your instructional above suggests- thats why I was at the point of troubleshooting the safety switch (I did get a new starter switch suspecting that, so now thats eliminated from suspect.

4) no power at other terminal of solenoid (since no power to the small wire, no power to the large terminal, right??)

5) no power to starter (again, no power to solenoid small wire)

6) not sure how to check G circuit, but can we eliminate this with all the other "knowns"? Just wondering. otherwise, have to do that check.

Remember- I checked continuity of that small wire to solenoid, and its good. maybe the grounding circuit is the key (pun?). Please advise........

thaks!!
 

Rivets

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I understand you are getting frustrated, but this is the first time you answered some of these questions. I now have more questions.

1. What is the voltage at the B terminal of the key switch?

2. What is the voltage at the S terminal of the key switch when the key is turned to the start position?

3. What is the model number of the unit for your unit, I need to look at a wiring diagram?

I know that you feel I am being a smart ----, but I don't have the unit in front of me and I am not doing the tests. You are doing the tests not me and I need your help to help you. Most units have two or three safety switches which may be causing the problem, plus some unit also route the wiring through the PTO switch.

I have been around the block twice and I stayed at a Holiday Inn, so I think I know a little about what I post. As I said earlier, electrical problems can be easy or hard to diagnosis. If you don't want my help, tell me to buzz off and I will stay out of your threads and not confuse the situation. If you want my help you must be willing to stop assuming things and actually check and test them before saying they are good or bad.
 

rigoletto

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I understand you are getting frustrated, but this is the first time you answered some of these questions. I now have more questions.

1. What is the voltage at the B terminal of the key switch?

2. What is the voltage at the S terminal of the key switch when the key is turned to the start position?

3. What is the model number of the unit for your unit, I need to look at a wiring diagram?

I know that you feel I am being a smart ----, but I don't have the unit in front of me and I am not doing the tests. You are doing the tests not me and I need your help to help you. Most units have two or three safety switches which may be causing the problem, plus some unit also route the wiring through the PTO switch.

I have been around the block twice and I stayed at a Holiday Inn, so I think I know a little about what I post. As I said earlier, electrical problems can be easy or hard to diagnosis. If you don't want my help, tell me to buzz off and I will stay out of your threads and not confuse the situation. If you want my help you must be willing to stop assuming things and actually check and test them before saying they are good or bad.

good deal, riv- i will do these checks and advise asap.......
 

motoman

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Follow Rivets lead. I think you know that corroded wire (even inside the insulation) , bad chassis ground connections (lug seating, paint interference, non-visible corrosion) will drop (reduce) voltage available . Can you check the battery electrolyte with a hydrometer? Voltage readings off battery terminals may be false as charge can build on surface of sulfated battery cells. Dirty battery surfaces and even battery clamps can drop voltage.
 

rigoletto

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ok, riv, here it is:

V at B is 12.63. V at S with key ON position is zero. Model # is 13A4 667 S118. Not 100% sure if the S is S or 5. My manual shows it as tecumseh model 667, hence, the 667 in the middle of the longer mod #. Thnaks, Man!
 

Rivets

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If you have no voltage on the S terminal we will have to start there. I'm going to make you jump through hoops, but I am not there to do my own checks. First, are you certain that you are checking the S terminal? Have you looked at the terminal itself and see an S stamped in the metal or next to the terminal? Are you checking the terminal or the wiring coming from it? How many terminals does your switch have and are all the terminals being used? Second, would you double check the units model number? I am not finding any listing or wiring diagram for any of the numbers posted in either of the threads you are posting. Finally, do you have a test light available, or just a VOM?
 

rigoletto

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If you have no voltage on the S terminal we will have to start there. I'm going to make you jump through hoops, but I am not there to do my own checks. First, are you certain that you are checking the S terminal? Have you looked at the terminal itself and see an S stamped in the metal or next to the terminal? Are you checking the terminal or the wiring coming from it? How many terminals does your switch have and are all the terminals being used? Second, would you double check the units model number? I am not finding any listing or wiring diagram for any of the numbers posted in either of the threads you are posting. Finally, do you have a test light available, or just a VOM?

OK, Riv- yes, I am 100% sure it was the S terminal, as I just troubleshot (a word??) that switch/ohmed it out, found a bad short, so ordered new. Message being, now I am very familiar with the G,S,M,Land B terms. It was definetly S. Its making more sense now cuz, as I stated before, Im suspecting the safety switch being faulty.

Otrher questions you had: I was checking the terminal blade itself- not the wiring attached to it. Switch has 5 terminals picture here:

Starter Ignition Switch for AYP Craftsman Cub Cadet MTD Murray John Deere More | eBay

as far as other model/ID #'s, all I have is Engine model OHV 130 206820B, Family TTp35 8UIG 2Ra, DOM 8036D, displacement 358. Model 667. Hope that helps, Riv. I can scan the wiring diagram I have, if it helps....

thanks
 
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