Car has been stood a while (off road). It needed a new alternator/power steering belt as old one had more or less disintegrated and power steering was thus non existent.

Fitted new belt and checked tension..PAS working fine. Checked battery charge..it was about 12.5v..& car started fine. Checked voltage with engine running and it was the same as when engine was off not 14v or similar.

Figured alternator not charging and when I checked with meter it was around 11.9 volts and did not rise when I switched headlights etc on. Then noticed that when switching the ignition ON that the red battery check light was not illuminated.

I took the green 3 way wiring connector out of the alternator, switched ignition to ON and tested the 3 wires of that connector with the meter's black probe connected to negative terminal on battery. Results were that terminal 1 (black/white wire) was below the battery voltage at 11.93v..terminal 2 in the middle WAS the battery voltage as expected and terminal 3 was 0.01 volts (I'm not sure what is normal?).

I know the T1 reading should be battery voltage doing this test and it's well below..in fact more or less the same reading as the alternator output voltage when the engine was running (11.9v).

As I believe the alternator won't work if the battery check light does not illuminate could a simple (!?) bulb replacement be the answer?...or maybe an internal alternator issue like dirty slip rings and poor contact with brushes?

All other warning lights work as they should. The car starts fine when charged up and idles fine too. I've not driven it properly for any distance but it seems to run ok.

Any thoughts?..thanks for reading

 

The readings you get with the plug disconnected appear about right.
The charge light should have illuminated with the Terminal 1 black/white wire earthed.
Terminal 2 (Yellow) is the feedback link (fuse OK)
Terminal 3 (Blue) is the ECU control link.

Would say you have an internal alternator problem

 

Many thanks for your reply Don..much appreciated.

"The charge light should have illuminated with the Terminal 1 black/white wire earthed."
I omitted to say that I had checked this when I was measuring the voltage yesterday and it did not come on.

I will remove the alternator and see what I can find..I guess a general clean up and checking the brushes would be a start point?

 

Looking at the Charging diagram if the ignition is switched on and pin1 of the plug is earthed the bulb should light up.
Circuit FB36 and Fuse 13 is the Combimeter supply.

Maybe there is a short across the bulb ??

 

Very kind of you to post on this again Don. I am trying to interpret your excellent diagrams but I am very inexperienced in the electrical side of automotive and this kind of schematic diagram.

When you say "Maybe there is a short across the bulb" ..I guess that would include a bulb that has for some reason failed/blown? ..or something else? How can I check that?..presume I have to get the instrument binnacle out?

Do you know which of the 2 fuse boxes fuse 13 is in?

 

As per diag Fuse 13 is in the "Fuse and relay box" - drivers right knee behind coin tray.



Arrangement in car - 10A red fuse bottom left

 

Fuse 13 in the interior fuse box has been tested in and out of the car..continuity is ok and in-car test with multimeter in DC mode reads same as the battery voltage so seems not to be a problem...& so does the Alt fuse in the under bonnet fuse box.

I guess the next step is to take the alternator off and inspect it for any obvious faults e.g. with brushes making contact to slip ring?

I don't think there's anything else I can do now to test the check the integrity of the charge warning light bulb (which never illuminates now) without removing the instrument cluster?..& I would imagine that's a pig of a job?

 

see attached

 

Many thanks for the .pdf Don. Will have a go when I get the time and report back to the thread.

 

anyone know what type of bulb (voltage/fitting descriptor etc) is needed to replace the battery check light?..I want to fit a filament/incandescent bulb not a LED.

Any link to a source would be appreciated

 

Bulbs are T5 / 12v 1.4w

cheap option from china
https://www.ebay.co.uk/itm/292022880602

 

many thanks

 

Removed instrument cluster..extracted & tested the battery check bulb with multimeter and it failed (no visible sign)...cracked it I thought...that was the cause. Took one of the Amazon bulbs as linked in the last post which arrived today ..tested it..fine.. we have continuity. Inserted the new bulb..tried it ..no dice!!..battery check light still does not come on as it should.

I wondered if something was blowing the bulb(s) so removed the new bulb and tested it again..it was fine.

Guess the alternator will have to come off.

 

Don, I note the Amazon bulbs linked (and bought) are 1.2v..whereas the Subaru 85066GA110 is rated at 1.4v, as are the Ebay ones you kindly linked. Should that make a difference here?

 

Rated at 1.2 Watts or 1.4Watts
Not a lot of difference

 

Think maybe there is a fault in the gauge cluster which means current is not reaching the new bulb(s..I've tried and tested several)...and alternator does not get therefore get "excited" and start charging.

I've read a few blogs/threads where people with similar a issue have added a "new" warning light to get around the issue a bad circuit board in the cluster...I guess by cutting and/or tapping into the b/w wire where it comes into the cluster connector (1 of 3) and connecting it to another suitable wire that is controlled by the ignition.

e.g. ..at about 5 minutes in.

Can anyone tell me the safest /best way to do this as the video was, to me at least, not as clear as it could be on the actual process of which wires to cut/tap into.