I'm challenging you.............
- Thread starter suprahero
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JJ and Jdub: You guys and your pointy-nosed jets!
Seriously, however, I had this problem several years ago and it disappeared after I had to replace my alternator...
Seriously, however, I had this problem several years ago and it disappeared after I had to replace my alternator...
Hey, the pointy end is the best seat in the house. The downside is you're the first to arrive at the scene of an accident. 
Since the regulator is integral to the alternator replacing the alternator fixes it if the regulator is leaky. Anyway, nice to know I'm on the right track.
Since the regulator is integral to the alternator replacing the alternator fixes it if the regulator is leaky. Anyway, nice to know I'm on the right track.
Ok...tried this out. Hope I did it correctly; electricial problems are not my strong suite
After I got home and poked around the engine bay, I remembered a couple of other details on my car...I have the 100 amp MR2 alternator installed. It fits like factory and plugs up with no modification. I have LED bulbs in the sockets for all the indicator and illumination lights on the dash. Another detail...the 3 lights are on dim only when the motor is running. With the key on, motor off the lights are fully lit bright as you would expect.
Don't have access to a scope, but I did use my digital multimeter (Craftsman). On millivolts, the darn thing gave me an error reading. For normal DC I got 14.22 volts at idle, 14.25 volts at 2000 rpm. AC did not register on the scale.
Did this (I assume you meant the 7.5 amp IGN fuse in the drivers kick panel). The battery light went out...the taillight failure and brake light remained on; very dim as described above with the motor running.
No effect at all. With the motor off, ignition on the lights are bright. Un-plugged the sensor...no change. Tried it with the motor on as well...all 3 lights are dim as previous. Un-plugged the sensor...no change. I applied the brake in both cases, the brake light remained the same....bright (no change) with the key on, motor off...dim (no change) with the motor running.
Thanks for your help JJ :icon_bigg And yeah...the pointy end is the place to be...the room with the view! LOL
After I got home and poked around the engine bay, I remembered a couple of other details on my car...I have the 100 amp MR2 alternator installed. It fits like factory and plugs up with no modification. I have LED bulbs in the sockets for all the indicator and illumination lights on the dash. Another detail...the 3 lights are on dim only when the motor is running. With the key on, motor off the lights are fully lit bright as you would expect.
jetjock said:
Don't have access to a scope, but I did use my digital multimeter (Craftsman). On millivolts, the darn thing gave me an error reading. For normal DC I got 14.22 volts at idle, 14.25 volts at 2000 rpm. AC did not register on the scale.
jetjock said:
Did this (I assume you meant the 7.5 amp IGN fuse in the drivers kick panel). The battery light went out...the taillight failure and brake light remained on; very dim as described above with the motor running.
jetjock said:
No effect at all. With the motor off, ignition on the lights are bright. Un-plugged the sensor...no change. Tried it with the motor on as well...all 3 lights are dim as previous. Un-plugged the sensor...no change. I applied the brake in both cases, the brake light remained the same....bright (no change) with the key on, motor off...dim (no change) with the motor running.
Thanks for your help JJ :icon_bigg And yeah...the pointy end is the place to be...the room with the view! LOL
CPT Furious said:
Yeah, mine actually started when my alternator failed...replaced it, but the problme with the lights being on dim with the motor running stayed.
Nice AVTR...is that a T-6? Good ole Enid by the sea
I was down at Laughin many moons ago.
LEDs and a different alternator? "Minor" details you failed to mention . Without going into all the technical ogga-booga the LEDs could very well be the problem.
I didn't mean the IGN fuse, I meant the 7.5 charge fuse in the fuse box. Unplug it with the engine runnning and see if the lights go out. Unplugging the IGN fuse won't check the regulator in the alternator.
The hand brake light (with the engine off) should increase slightly in brightness when the brake is applied.
It sounds like the light sensor box isn't the culprit but you need to pull the charge fuse to check the regulator. If the lights go out the regulator is leaking. If it's bad it'll leak a ground path with incandescent lamps but it's likely to leak with LEDs even if it's OK. If that's the case you're either going to have to add some resistance to ground in the circuit or go back to regular lamps.
. Without going into all the technical ogga-booga the LEDs could very well be the problem. I didn't mean the IGN fuse, I meant the 7.5 charge fuse in the fuse box. Unplug it with the engine runnning and see if the lights go out. Unplugging the IGN fuse won't check the regulator in the alternator.
The hand brake light (with the engine off) should increase slightly in brightness when the brake is applied.
It sounds like the light sensor box isn't the culprit but you need to pull the charge fuse to check the regulator. If the lights go out the regulator is leaking. If it's bad it'll leak a ground path with incandescent lamps but it's likely to leak with LEDs even if it's OK. If that's the case you're either going to have to add some resistance to ground in the circuit or go back to regular lamps.
jetjock said:LEDs and a different alternator? "Minor" details you failed to mention
I didn't mean the IGN fuse, I meant the 7.5 charge fuse in the fuse box. Unplug it with the engine runnning and see if the lights go out. Unplugging the IGN fuse won't check the regulator in the alternator.
The hand brake light (with the engine off) should increase slightly in brightness when the brake is applied.
It sounds like the light sensor box isn't the culprit but you need to pull the charge fuse to check the regulator. If the lights go out the regulator is leaking. If it's bad it'll leak a ground path with incandescent lamps but it's likely to leak with LEDs even if it's OK. If that's the case you're either going to have to add some resistance to ground in the circuit or go back to regular lamps.
Yeah...I know
I apologize...didn't dawn on me until I went out to the garage this afternoon. And I actually thought the same thing...the LEDs might not be providing the resistance necessary. When I was pulling the plug on the taillight sensor, I remembered how the turn signal lights "hyper" flashed for the same reason...had to go back to standard bulbs for the turn signals to work right.Concerning the charge fuse...where exactly is it? On my '89, the only 7.5 amp fuses in the kick panel are the Gauge, Radio, Turn, and IGN...none are marked "Charge". There is a 15A Engine fuse and a 15A ECU-IG fuse.
Under the hood, there are no 7.5 amp fuses...they are marked:
1 - RTR 30A
2 - empty
3 - Head (LH) 15A
4 - Head (RH) 15A
5 - Haz-Horn 15A
6 - Dome 20A
7 - EFI 15A
8 - ALT 100A
Huh. Toyo changed stuff I guess. My 87 has a charge fuse under the hood. It's inline with "L" (lamp) output on the alternator. Look in your TSRM and see how that line is wired. I mentioned it because the charge fuse is an easy way to open the L line but if you don't have it you'll have to find another way to do it. Maybe disconnect it right at the alternator connector but look in your book first. I'm betting the problem is from using LEDs though. People forget they're not lamps...they're diodes.
If you can't disconnect the L line try connecting a small 12 lamp to it and the alternator case. If the LEDS go out there's your problem. You can leave it there if you like
Btw I haven't forgotton you. I went abroad before I had a chance to send you a little something but it'll happen when I get back.
If you can't disconnect the L line try connecting a small 12 lamp to it and the alternator case. If the LEDS go out there's your problem. You can leave it there if you like
Btw I haven't forgotton you. I went abroad before I had a chance to send you a little something but it'll happen when I get back.
jetjock said:Huh. Toyo changed stuff I guess. My 87 has a charge fuse under the hood. It's inline with "L" (lamp) output on the alternator. Look in your TSRM and see how that line is wired. I mentioned it because the charge fuse is an easy way to open the L line but if you don't have it you'll have to find another way to do it. Maybe disconnect it right at the alternator connector but look in your book first. I'm betting the problem is from using LEDs though. People forget they're not lamps...they're diodes.
If you can't disconnect the L line try connecting a small 12 lamp to it and the alternator case. If the LEDS go out there's your problem. You can leave it there if you like
Btw I haven't forgotton you. I went abroad before I had a chance to send you a little something but it'll happen when I get back.
LOL...NP. I was feeling like a Noob tho...scratching my head "where is that damn fuse"....
Ok, here's what I did (reference the attached diagram): I took a test light grounded to the alternator case and went through the 3 wires with the motor running.
B-Y wire - test light lit, no change on the 3 problem lights in question
Y-G wire - test light was off, but the 3 lights (brake, taillight, and battery) went from dim to full bright.
W wire - test light lit, no change on the 3 problem lights in question
Hmmm...now ya got my curiosity going
The Y-G is the lamp line. My car has a fuse inline with it, yours doesn't. I also don't see where it's connected to the combo meter in the same way as mine so I don't see how it can influence the other lights. Shoot, this entire thing was reasoned out based on circuit analysis. The problem is your circuits are different
The lights went full bright because you were supplying a ground through the test light filament. I expected the regulator to shut the line down with the added load but no dice. It may be that alternator doesn't use a Type M regulator like the stock one does and since everything was predicated on that we're back to square one. The diagram shows a Type M but it's not the same alternator that's now on the car.
You need to isolate that L line somehow. Either push the connector pin out or unplug the connector and place a piece of tape over the pin and plug it back in. However if there is no connection to the other lights that won't help either. Can you post up the schematic for the 89 combo meter? What about the hand brake? Does it do what I said?
The lights went full bright because you were supplying a ground through the test light filament. I expected the regulator to shut the line down with the added load but no dice. It may be that alternator doesn't use a Type M regulator like the stock one does and since everything was predicated on that we're back to square one. The diagram shows a Type M but it's not the same alternator that's now on the car.
You need to isolate that L line somehow. Either push the connector pin out or unplug the connector and place a piece of tape over the pin and plug it back in. However if there is no connection to the other lights that won't help either. Can you post up the schematic for the 89 combo meter? What about the hand brake? Does it do what I said?
Ok...here's my plan: I looked at the alternator connector; the only way (I can see) to isolate the "L" line is to install an in-line fuse block or cut the wire. I'll have to head over to Ace Hardware and get one...I'll use a 7.5A fuse. I'll let you know what the result is.
I did the emer brake with the taillight sensor disconnected. As before, the 3 lights are dim only when the car is running, but I did it both ways.
Ignition on, motor off - all 3 lights were bright with the sensor un-plugged. Pulled the emer brake up...no change.
Motor running - all 3 light were dim as before with the sensor un-plugged. Pulled emer brake up...brake light went bright, no change in the other 2 lights.
Tried both of the above with the sensor plugged in just for grins. Got identical results for each when I pulled the emer brake up...ignition on, motor off - bright, no change and motor running - brake light bright, no change for other 2 lights.
I attached the Combo Meter diagram from my TRSM...funny, it shows a charge fuse on the "L" line below the charge light. I looked again...it's nowhere to be found.
I did the emer brake with the taillight sensor disconnected. As before, the 3 lights are dim only when the car is running, but I did it both ways.
Ignition on, motor off - all 3 lights were bright with the sensor un-plugged. Pulled the emer brake up...no change.
Motor running - all 3 light were dim as before with the sensor un-plugged. Pulled emer brake up...brake light went bright, no change in the other 2 lights.
Tried both of the above with the sensor plugged in just for grins. Got identical results for each when I pulled the emer brake up...ignition on, motor off - bright, no change and motor running - brake light bright, no change for other 2 lights.
I attached the Combo Meter diagram from my TRSM...funny, it shows a charge fuse on the "L" line below the charge light. I looked again...it's nowhere to be found.
Before doing any cutting, I suggest putting the incandescent charge indicator bulb back in. I suspect the problem is that the LED light is more sensitive than the original bulb, and is responding to a very small current that normall flows but is too small for the incandescent bulb to respond to.
I agree 3p. I've suspected that since hearing he used LEDs. Opening the L line will prove that's the source of the ground leakage but if I were him I'd put the lamps back in. I've never had a failure of any of my dash lights. The bulbs are the ones that came with the car.
Jdub: Ok, lemme look at that a bit. Automotive charging systems are pretty simple but I don't have prints for that year car. But I do have an extensive library of other stuff that reveals a great deal more than the TSRM does and if you're bent on keeping those LEDs we'll figure something out. Still, it'd be a lot easier if I was there.
edit: Ok, your meter is wired different from mine. The isolation diodes in the combo meter are the only connection between the three lights. Has to be either a faulty regulator or the LEDs are simply responding to the small leakage current being passed by the transistor in the regulator.
Jdub: Ok, lemme look at that a bit. Automotive charging systems are pretty simple but I don't have prints for that year car. But I do have an extensive library of other stuff that reveals a great deal more than the TSRM does and if you're bent on keeping those LEDs we'll figure something out. Still, it'd be a lot easier if I was there.
edit: Ok, your meter is wired different from mine. The isolation diodes in the combo meter are the only connection between the three lights. Has to be either a faulty regulator or the LEDs are simply responding to the small leakage current being passed by the transistor in the regulator.
Thank you Gentlemen - The more I think about this (yes it hurts...LOL), the more I suspect you guys are correct...it's the LEDs. I used them because I had the dash out replacing a speedo cable and it seemd like a good upgrade...as with many things on this car, that doesn't seem to be the case :3d_frown: I'm not hellbent to use LED lights for these indicators...I will replace them with std bulbs. I'll let you know how it comes out.
This thread is pretty freaking long; so I'm not going to take the time to read it all. HOWEVER; this has been happening on my car for approx. 2 weeks now.
I finally figured out what it was. The big circle thing that plugs into the alternator is what causes it. The wires get lose/move during accell wind moving and mine are nice and dried and cracked. I'm gonna wire in some new wire and heat shrink it in the next couple days. But it is definately the alternator wires which cause this. It was happening way more when my IC piping was grounding out on the alternator but after I stuck some cardboard between them it stopped for a bit then the lights came on. I went and wiggled the wires while my wife sat in the car and had her tell me when the lights went off.
Cheers,
Kyle Ackerman
I finally figured out what it was. The big circle thing that plugs into the alternator is what causes it. The wires get lose/move during accell wind moving and mine are nice and dried and cracked. I'm gonna wire in some new wire and heat shrink it in the next couple days. But it is definately the alternator wires which cause this. It was happening way more when my IC piping was grounding out on the alternator but after I stuck some cardboard between them it stopped for a bit then the lights came on. I went and wiggled the wires while my wife sat in the car and had her tell me when the lights went off.
Cheers,
Kyle Ackerman