1. Can’t make it to the GIE+EXPO 2017?
    LawnSite brings the trade show floor to your fingertips with our new GIE+EXPO 2017 Sneak Peek video series debuting now in the Lawn Mowing forum.

    Dismiss Notice

62" Toro wont start

Discussion in 'Mechanic and Repair' started by birddseedd, Mar 9, 2013.

  1. ricky86

    ricky86 LawnSite Silver Member
    Messages: 2,068

    A voltage drop test is the displayed voltage when probes are on the same wire. Like terminal to terminal, with the circuit energized. Like pos battery POST to the POST on the starter. Displayed voltage is the drop.
    If I understand you correctly, you should have approx the same voltage, 12.3 at the blue wire. You are backprobing the jack?
    You did state the pump activates?
    If the pump activates, that shows the coil side of the relay is ok (most likely). If you have 12.3 at the brown, with the key in start and only .03 at the blue, it must be the relay, or a connection problem.
  2. birddseedd

    birddseedd LawnSite Silver Member
    Messages: 2,111

    yes the pump comes on. in fact if I switch all then safety switches it comes on.

    I thought I was doing a voltage drop test on the relay. I guess I did it wrong. that's just how the guy on YouTube showed it. wire to ground before a load and wire to ground after the load. if there is anything showing up after the load that is the drop. is this not correct?

    if I disconnect the blue wire and take it to ground its 12 v
  3. birddseedd

    birddseedd LawnSite Silver Member
    Messages: 2,111

    youtube.com/watch?v=BG9U7uOcEeY is what I watched
  4. fatboynormmie

    fatboynormmie LawnSite Bronze Member
    Messages: 1,269

    Hey birdseedd I messed up part of my last post when I started explaining the coil side terminals of the relay which should be 85/86 on relay.To perform a voltage drop test across the coil side of relay place your meter tip(+) on 85 and the (-) on 86 and power the relay.You are reading across the relay and you should see almost zero volts with circuit energized.

    To test the the contactor side of relay for voltage drop your meter (+) should be on terminal 87 or 87a (one or the other) and put the (-)on terminal 30.Power the circuit and you should see once again close to Zero voltage.

    While the relay is energized and you read any voltage drop other then close to zero volts across the relay on either side coil or contactor you have a faulty relay .

    On a digital multimeter always use (voltage) setting for testing here's why

    If you touch the red and black leads together the meter should read (0)volts which in turn means they are actually shorted together .Works just like testing continuity but more accurate because the circuit is actually energized.(STOP USING THE CONTINUITY SELECTOR it will bite you in the AZZ. Power has to be off and and circuits have to be separated to actually get a good continuity check).

    Hold the leads away from each other and you usually see whats called ghost voltage and the meter jumps all over the place.This is basically showing you an open.

    There can only be three problems with wiring short ,open and high resistance(voltage drop) that's it . And all can be trouble shot with a digital multimeter using the selector in (voltage) with the tips in this paragraph.

    Hope this helps:waving:
  5. birddseedd

    birddseedd LawnSite Silver Member
    Messages: 2,111

    silly question here. but how do i know know which post is which contact? there is a diagram on the relay showing the functions of each post (the 5th one im a little confused on, 2nd ground?) but unlike other relays iv used, it does not show which one is which.
  6. ricky86

    ricky86 LawnSite Silver Member
    Messages: 2,068

    Maybe we'll try a different approach.
    1)Put the relay back in. Black meter lead to - post on battery. Red to +. Turn key to start. What's you're reading? (must be 9.5 minimum)
    2) Move the red lead to the sol post. What's your reading? (must be 9.5 minimum)
    3) If your readings are within .5 ~ 1 volt, remove and bench test starter.
    4) If not, make a jumper lead, remove relay, install jumper into jack, one end in the brown wire and the other in the blue. Key switch to start. Does the starter turn? Yes? most likely the relay.
    5) If not trace the blue wire back to the jack, across the jumper to the brown back to the key switch until you find the spot you lose voltage keeping in mind key switch must be in start position.
    If you skip a step, you will be doing what we call in the industry as "Stepping on you d**k"
  7. ricky86

    ricky86 LawnSite Silver Member
    Messages: 2,068

    Coil is 85 +86
    30 is common (12v in this application from key switch)
    87 + 87a are circuit.
    When energized 30 and 87 connect
  8. fatboynormmie

    fatboynormmie LawnSite Bronze Member
    Messages: 1,269

    I think your getting confused with the 3 terminals on the( power or circuit side)
    87=normally open
    87a=normally closed

    Normally open means there's( zero) continuity between 87 and 30 while coil circuit it off

    Normally closed means there (is) continuity between 87a and 30 while coil circuit is off

    There can only be one wire attached on that side of the circuit and it leads either to 87 or 87a depending on how the circuit works.Usually on the bottom side of the relay where the male spades stick out there should be numbers corresponding to the spades and you should be able to actually see where the harness is running up into the relay connector to see how its wired.From what ricky has stated it should be the top spade(87) and the bottom (30)
  9. birddseedd

    birddseedd LawnSite Silver Member
    Messages: 2,111

    It was the relay.

    jump wire from brown wire (post 30) would start the engine
    jump wire from blue wire (post 87) would not.

    I have not had a chance to read over everything in the last couple posts. i appriciate the help. ill be reading it over to learn how to do the voltage drop test.

    now to try to filter everything out of my pump before putting my wheel motor on.

    thanks again
  10. birddseedd

    birddseedd LawnSite Silver Member
    Messages: 2,111

    oh. and a note about ford.... it would help if they would label what posts are what on their relays.....

Share This Page