24V HJ61 - Thread name edited: Charging problem caused by a one of hell well hidden little wire added by the previous owner (1 Viewer)

[David*BJ70]

HJ61 24V LHD

While I had a problem with my alternator which suddenly stopped charging, relying on certain other posts, I did not even look for the existence of the Charge Light Relay believing that it was non-existent on my vehicle. It was a huge mistake because after hours of testing and investigation and a new regulator, I found my Charge light relay behind the passenger footwell cover (Not even where the FSM indicated, nor where it seemed to be according to ToyoDIY!).

I tested it as described by the FSM page CH-24 and it is not functional ---> no continuity between terminals 1 and 4.

The root problem is the following:

- On vehicle, all wires plugged in, the alternator suddenly stopped charging.
- On bench test the alternator works (this test done at the shop allowed me to see the test was carried out with only terminal B connected)
- Back on the vehicle with only terminal B connected, it charges... as soon as the green plug is connected, it stops charging.

BTW, the Light is always ON except when relay is removed

I literally tested everything, each possibility (except, at that time, the Charge Light Relay). I even change the regulator.

On the alternator, there is voltage on terminal B and, when engine running, on terminal L of the green plug on the alternator side.

When the green plug is unplugged, there is Voltage on Terminal F but it dropped to 0V when the green plus is plugged :

So, is it possible that a non-working Charge Ligtht Relay is causing the alternator to stop charging?

Now I'm looking for an Charge Light Relay 27790-57010.

Is there a way to by-pass the relay ?

 

[veiloctane]

awesome thanks for the documentation!!!

 

[charlay61]

HJ61 24V LHD

While I had a problem with my alternator which suddenly stopped charging, relying on certain other posts, I did not even look for the existence of the Charge Light Relay believing that it was non-existent on my vehicle. It was a huge mistake because after hours of testing and investigation and a new regulator, I found my Charge light relay behind the passenger footwell cover (Not even where the FSM indicated, nor where it seemed to be according to ToyoDIY!).

I tested it as described by the FSM page CH-24 and it is not functional ---> no continuity between terminals 1 and 4.

View attachment 3405272

The root problem is the following:

- On vehicle, all wires plugged in, the alternator suddenly stopped charging.
- On bench test the alternator works (this test done at the shop allowed me to see the test was carried out with only terminal B connected)
- Back on the vehicle with only terminal B connected, it charges... as soon as the green plug is connected, it stops charging.

BTW, the Light is always ON except when relay is removed

I literally tested everything, each possibility (except, at that time, the Charge Light Relay). I even change the regulator.

View attachment 3405261View attachment 3405262

On the alternator, there is voltage on terminal B and, when engine running, on terminal L of the green plug on the alternator side.

View attachment 3405268


When the green plug is unplugged, there is Voltage on Terminal F but it dropped to 0V when the green plus is plugged :

View attachment 3405270

So, is it possible that a non-working Charge Ligtht Relay is causing the alternator to stop charging?

Now I'm looking for an Charge Light Relay 27790-57010.

Is there a way to by-pass the relay ?

Can you pop open the relay and have a look at the 2 zener diodes ? Checking continuity of the relay coil will be different as it has 2 zener diodes in series. It will only work 1 way with a multimeter and sometimes only with a proper multimeter with diode mode. If the relay is truly unobtainable, then you can try repairing yours. Pry it open and have a look at the inside for burnt stuff and those 2 diodes. Do you have a multimeter with "diode mode" ? You would be able to measure the forward voltage of the diodes ? I have never seen the inside of those relays, however, zener diodes are cheap and could be replaced.

As for the charging not working if the relay is out... i am unsure if its going to affect the charging function. For sure, the light will not turn on in your dash as the light is turned on by the normally closed contact. When "L" is outputing a high enough voltage, it should go through reversly through the zener as it goes above the reverse breakdown voltage and thus energizing the coil. So check the diodes first. I do not know how the ic works, however, you could try putting a small load between pin 1 & 4 of the charging light relay using some jumper cables and any other relay coil. Maybe the IC needs to see a "small current" on pin "L" in order to allow the bigger current to output.

 

[charlay61]

One more question, do you have a good 24Volt at the IG terminal ? With the key at run ?

 

[David*BJ70]

@charlay61

Je vois que tu habites au Québec alors on pourrait communiquer plus aisément en français au besoin ... but for the benefit of the group, let's continue in English

Really thank you for these answers but I believe that the internal analysis of the relay exceeds my capacities of investigation.

A local Cruiserhead gave me a relay yesterday which like mine doesn't work so at least I have 2 if I want to test but again this I believe is beyond my capabilities.

As for the Voltage of the IG terminal, vehicle side, it is the same as what the batteries give.


I did a few other tests:

I checked whether from the green plug, vehicle side, there was continuity up to terminal 4 of the plug for the relay. I did the test separately green plus -> fuses box AND fuses box -> terminal 4 Relay plug and finally, Green plug to terminal 4 of the Relay plug: continuity.

Note this: while on the alternator side, I have Voltage on L, when I plug in the Green plug and the vehicle is running, I have no Voltage going from alternator to terminal 4 of the plug relay AND the alternator stops giving Voltage to its source on the connection on the regulator.

I will need to investigate why the alternator stop when the connection between it ant the relay is plug.

While I thought I was good and narrowed the solution … it look that I’m not done at all !

Now I'm totally fed up. I'll leave you with that for today. I've got a lawn to mow and a pool to clean.

Next test is to apply voltage in the green plug to feed 24+V to the terminal 4 while the engine is not running

 

[carbon60]

Discussion of repairing he charge light relay:

Post in thread 'Charge light relay...'
Charge light relay... - https://forum.ih8mud.com/threads/charge-light-relay.1100863/post-14803324

 

[David*BJ70]

Please help me understand if me relay work.

I had a talk with a friend and he bring me the fact that a diode work like a one direction channel and continuity may not be total.

Upon the FSM it should have continuity between 1 and 4.

Depending how I put my multimeter probe, I get these results:

See red and black probe position :

So, did I have a Charge light relay in good working order ?

As state above the next testing area will be between L and 4 where I may have a short or something and that “tell” my regulator to stop charging… But …Latter

 

[charlay61]

Please help me understand if me relay work.

I had a talk with a friend and he bring me the fact that a diode work like a one direction channel and continuity may not be total.

Upon the FSM it should have continuity between 1 and 4.

Depending how I put my multimeter probe, I get these results:

See red and black probe position :
View attachment 3406346View attachment 3406347

So, did I have a Charge light relay in good working order ?

As state above the next testing area will be between L and 4 where I may have a short or something and that “tell” my regulator to stop charging… But …Latter

itdon't know exactly this relay works, but i can assume how it works. Normal diodes only work one way. Zener diodes work like a normal diode with forward voltage but they also let the current pass the otherway only if the voltage is above a certain thresold.
If i were to make that relay, i would make it that the reverse voltage of both diodes would have to be above 26volts in order to turn on the relay indicating the charging "is okay". let's say you would use 2 zener diodes in series with each a reverse breakout voltage of 13v, you would need at least 26volt for the relay to energize. Indicating that your alternator is charging.

 

[David*BJ70]

You and I who have these old LCs have all at one time or another experienced a problem. We try to be methodical. We do the tests suggested by the FSM. Then we go to the periphery.

And we dig,
We dig,
And we dig,

We think, figure, speculate...

In my problem, I managed to eliminate each of the probable sources of my problem. In the end, I came to the conclusion that the problem was between L of the alternator's green plug (truck side) and 4 of the Charge Light Relay, more precisely, either between L and the Charge fuse or between the Charge fuse and 4 of the Charge Light Relay.

So I started by stripping the wire coming from the green plug. The whole thing, believe me, seemed very original, only to discover that the previous owner, over 15 years ago, had added a wire to take a voltage source from the L wire (!!!!!). This added wire was wedged between 2 body panels and after thousand of kilometers + ended up stripping and creating a short.

The alternator regulator "sensed" that then stop charging.

So, I don't know what to learn from this. It wouldn't necessarily allow me to approach the next electric issue differently. I don't know if I should have been looking for a short in the first place.

In the end, all that time, all that money invested... all that anger and discouragement was caused by a wire that shouldn't have been there and created a hidden short in the fender.

One hell of a little wire !


BTW, who think taking tension from the L wire is a good idea !?!?!

 

[hj 60]

But we all learned so accept all those happy thoughts
Maybe L was used as a rpm indicator or some sensor dash thing?