414-8 Relay

[smitty316 0]

I'm still trying to figure out why I can't start my 414-8 with the ignition. Some previous owner added a starter switch that does the job, but I really want to get it back to original. From what I can tell the ignition switch is ok.

The red wire from the ignition ( to the solenoid was cut and the fuse removed. I replaced the fuse and connected the wire to the battery terminal on the solenoid like I see it in the wiring diagram. Everything else seems fine. (oh yeah, I repaired a bunch of mouse damage).

From studying the wiring diagram, I keep going back to the relay. I don't fully understand how it relates to everything, but it looks like it could possibly be a suspect. Is there a way to test it?

Thanks, Smitty

[smitty316 0]

I just found out that if I run a wire from the S of the ignition directly to the purple of the solenoid, the ignition will start the tractor. (This purple goes from the switching relay to the solenoid.) Than means I'm bypassing the PTO switch, the clutch neutral switch, the oil level switch and the switching relay.

When I test the oil switch it shows a closed circuit. Shouldn't it be open? If so, maybe that's the culprit.

Thanks,

Smitty

[smitty316 0]

I just tested the voltage to the low oil switch. There is 12V going in, but zero coming out. When I shorted across the two terminals for this switch I only get a clicking sound at the switch relay (it didn't do that before). If the low oil switch were bad I'd think this shorting across would make it start.

I also tested the voltage coming out of the clutch neutral switch. it reads 10.3 V there. This is before it goes into the switch relay.

From looking at the diagram, the PTO interlock switch must be working to get voltage at the Clutch neutral switch since it comes first in that circuit.

Does this make any sense to anyone?

Smitty

[Save Old Iron 1,563]

Sorry Smitty, I was on vacation and away for a few days.

I just tested the voltage to the low oil switch. There is 12V going in, but zero coming out.

This is as it should be. Looking at the wiring diagram, if the engine oil is low, the oil switch closes its contacts and powers up the OIL LEVEL RELAY. When the OIL LEVEL RELAY is energized, the internal contacts prevent power from reaching the STARTER RELAY coil, thus keeping the engine from cranking.

So the OIL LEVEL SWITCH and the OIL LEVEL RELAY appear to be functional. The OIL LEVEL RELAY may still have some internal mechanical / contact issues not allowing proper electrical operation of the STARTER RELAY. Read on - we can easily test for internal relay issues.

I also tested the voltage coming out of the clutch neutral switch. it reads 10.3 V there. This is before it goes into the switch relay.

You did not mention if the 10.3 volts was measured when the ignition switch was turned to the START position. I assume the voltage dropped to 0.0 V when you released the ignition switch from the start position.

PLEASE CONFIRM 0.0 when ignition switch is not in START and 10.3 v when ignition switch is in START position.

The 10.3 volt reading is a little strange. Since the engine is not cranking, battery voltage should still be around 12. something volts. If all the switches in the safety circuit are working well, their internal resistances should be very low (fractions of an ohm) and ALL BATTERY VOLTAGE SHOULD BE DROPPED ACROSS THE LOAD - which is the STARTER RELAY coil.

If 2+ volts are being dropped across the OIL RELAY, PTO switch or CLUTCH switch, then we need to isolate the culprit "stealing" voltage from energizing the STARTER RELAY.

Measure across the OIL LEVEL RELAY contacts first - then head to the PTO switch and CLUTCH switch with the same test. One is bound to be introducing an excessive voltage drop. The ignition switch may also be worth measuring for voltage drop at the START terminal.

[smitty316 0]

Thanks Chuck,

First, the voltage goes to 10.3 when in the start position and then back to 0.0 when I let off the key.

Also, the wiring diagram I am using (1989 414-8) does not show that Oil Level Relay. It shows the Oil level switch and a Switching relay. I don't think my tractor has a Oil level relay unless I'm overlooking it.

I did run a wire from the S of the ignition to the Pu wire that runs between the Switching relay and the solenoid. This allowed the tractor to start with the ignition. I assume that narrows it down to the oil level switch (which seems to be working), the PTO switch, the Clutch switch and the Switching relay since they're all in between those two points. Since then I removed the PTO switch and found one of the two triggers missing and the other badly corroded. The Parts Tree drawing shows each half of that switch with a trigger so I'm assuming it's bad. I ordered one so hopefully that's the case.

I got the 10.3 V. coming out of the Clutch neutral switch. The way I read the drawing that test included the PTO and Clutch neutral switch at the same time, but I'm assuming it's the PTO switch that's the problem.

Does that make sense?

Smitty

[Save Old Iron 1,563]

Smitty, I am not sure if there are different copies of the Demystification guides floating around so we will make sure we are both reading off the same page.

In the 414-8 1989 section of the guide, page 7-82, the whole tractor schematic is presented. Directly above the "CLUTCH NEUTRAL SAFETY SWITCH" callout is the oil level relay labeled only as "RELAY". Directly above the oil relay is the starter relay labeled "SOLENOID".

This diagram of the entire tractor wiring can be a little confusing so the guide breaks down the wiring to just the starter function on page 7-83. The diagram on this page shows the connections in the starter system with an oil level that is "OK". In this diagram the "RELAY" on page 7-82 is relabeled "OIL LEVEL RELAY"

On page 7-85, that same diagram is redrawn to show the relay contacts in the "OIL LOW" condition. The "RELAY" is also called out as the "OIL LEVEL RELAY".

For the purpose of clarity in further conversations, we should agree to call each by its own function - "starter relay" and "oil level relay".

WE ALSO NEED TO VERIFY YOUR TRACTOR INDEED HAS THE OIL LEVEL RELAY PRESENT. PREVIOUS OWNER MAY HAVE BYPASSED / REMOVED THE RELAY. Follow the purple wire back from the starter relay and it should plug into another canister with three tabs with the metal case of the canister grounded to the frame of the tractor. I believe this part is called out on the PartsTree site you mentioned earlier.

A second way of confirming the identity of the oil level relay is, as you mentioned earlier, jumper the oil level float switch leads and listen for a relay clicking. I would believe this to be the OIL LEVEL RELAY activating / deactivating.

The OIL LEVEL RELAY could be a contributor to your non start issue. The contacts inside the relay body appear to mechanically functional (clicking heard) but this clicking does not mean the contacts are clean and able to support current flow to the starter relay. So mechanically good, but electrically bad. Very possible in all solenoid / relay situations.

The PTO switch with corroded tabs could also be a contributor. Jumping the tan and purple leads of the PTO switch effectively removes it from circuit.

So in simplest form, here is what we are dealing with

in the diagram above, please note we are measuring DC volts ACROSS EACH COMPONENT - NOT IN RELATION TO GROUND.

All the micro switches and the ignition switch should have virtually no voltage dropped across them (shown as 0.1 volts on meter) and the only load in the circuit, the starter relay, should have nearly the entire battery voltage dropped across its coil.

keep us updated

:woohoo:

[smitty316 0]

Chuck, This is the info. below to see the wiring diagram I am looking at. It doesn't show the Oil level relay like the diagram you are using. I'll look again at my tractor, but I don't think it came with one.

Thanks again, Smitty

http://groups.yahoo.com/group/wheelhors ... rmanuals3/

named

Tractor 1989 414-8 31-14K804 Wiring Detailed.pdf

[smitty316 0]

Chuck, My mistake!! I just realized that they use two different names on the different diagrams. The Oil Circuit diagram does call it the Oil level Relay. All the other diagrams simply refer to it as the Switching Relay.

So now we're on the same page.

Sorry about that,

Smitty

[Save Old Iron 1,563]

Smitty , I downloaded the Yahoo link - it is the same diagram as in the Demystification guide

Here is the diagram from the Yahoo link

with the oil relay and the starter relay highlighted.

[smitty316 0]

Yes, This makes sense now.

When you show "voltage drop", what position is the key in? Also, could this same test be done by checking for resistance resistance?

Just to make sure I understand, your pictures show the switches consuming 0.1 volts parallel to the switch with current running through it?

Also, when I did jump across the oil switch earlier I did hear the clicking in the Oil relay switch. Can it be taken apart to clean the contact points?

Thanks again. This is an amazing website. Smitty