Charge light diode/resistor

[Granto]

Just when you thought all alternator questions have been answered..

anyone know how to check the resistor on the back of the AE86 dash?

The one connected to the orange/black wire.

Should it have continuity?

I think that is dead, therefor, my alternator light is not working. However, I cannot even find it mentioned in the electrical diagrams.

Camera is dead though, so I can't take any more decent quality pics.

The thingie is black with a blue end on it, and says, 1R below that is 10E and below that is 3G

Attachment 4485
Attachment 4486

Any help would be appreciated. I mean, I really just can't get the light to come on! heh.

Thanks, Grant.

[highrolla]

Have you checked that you have 13-14.5v across your battery?

If not then your problem is the alternator not the resistor.

If you have a Nippon Denso alternator or any for that mater your problem is either
1. Brushes
2. Diode pack
3. Voltage regulator

Most likely will be the brushes..

Have a look at how they come apart here:

I had the diode pack go on mine which took with the voltage reg aswell.

I got the parts from a wrecking hard to rebuild it

http://www.4x4wire.com/toyota/tech/alternator/

If it is a bosch then then the brushes and voltage reg are in one little unit that requires 2 screws to be undone at the back..

[river]

Hi,

Has it only got two legs... or soldered onto the board in only 2 places?

1R usually means 1 ohm.

Not sure about the 10E, unless it's a decimal multiplier.. such as x.1... which would make it a .1ohm (1 x .1) resistor. 3g???? maybe size, rating or tolerance specification... not sure.

Sorry, I wasn't much help there.

seeyuzz
river

[BradW]

Is it a resistor or a diode. The wiring diagram you linked to shows a diode and the picture you linked to says

Diode is on the other side of this circuitboard type thingo

To check it, get a test light and check for power at the alternator light. If you have power at the light, then the diode is OK.
If you have power on one side of the light, connect the test light to the other side of the light and it should light up. If it doesn't then it is probably a blown globe. If the light does light up, then you need to check the wiring between the dash and the alternator.

Hope this is helpfull.

[Granto]

To test the check light, I attached the alternator light that's meant to goto the alternator to the battery -ve. I get a -ve at the dash. I get 12v-ve at the dash too so that's all good. The 12v+ve seems to end at that diode. I.e. I get 12v+ve at +ve for test light in the dash plug, which goes upto where the diode is, however, the other side of it is

I have Earth at the battery light, but not power (it stops where that diode is).

So if the diode is meant to be 1way/1ohm resistance or whatever, then, it appears to be working incorrectly. cos there is infinite resistance between one side and the other.

What I don't know about electronics could fill the stadium though

[The Witzl]

A diode is a one-way current device. Current can flow one way, but not the other.
your multimeter there should have a diode test mode.
In diode test mode, putting the probes on the diode one way will not work (open circuit), and putting the other way will work.

The symbol for a diode is

usually on those circuit board thingies, it'll have this symbol somewhere near the diode. The arrow points in the direction of current flow.

[Granto]

Okay cool, thanks for that.

I guess they thought people would automatically know that

hrm, one way it's infinite resistance, the other way it says "600".. so I guess that's working.

I don't get why I only have current on one side of it and not the other though, seeing as in the direction it's pointing is where the current stops.

Grant.

[Granto]

okay so yeah using that diode test function on multimeter, it's reading between 560-600.. i don't know what unit of measurement that is in though.

so that's really weird

if it's working, i don't get why it dosen't have power on both sides of the diode, perhaps i should replace the diode with a wire, hrm.

Grant.