skir2222

I have a 87 turbo2 with a S5 alt. I have 1 plug in the back of my alt, one wire is black with a white strip and the other is a white wire with a black stripe I believe.

I unplugged the plug from the back of the alt. and stuck a wire into the white wire with the stripe and grounded it, lights did not come on at all.

So should I pull the kickpanel and ground the yellow/blue wire or is there another way to go about fixing this?

HAILERS

Pull the yellow/blues plug off and gnd the yellow/blue. IF the key is ON or better, all the warning lights should come on. IF they don't the problem lies in the warning light cluster.

And ask yourself this...when you put the WHITE/BLACK to gnd, did you hear the alternator relay inside the CPU make a click???? IF I can hear this click from the engine bay you should also be able to hear it. The click confirms the gnd on the WHITE/BLACK is indeed pulling in the alt relay inside the CPU.

If gnding the yellow/blue does not turn all the warning lights on...........then it's most likely the warning light assy needs the solder on the warning light assy plug reflowed. NOt the harness plug, but the jack on the warning light assy.

skir2222

Pull the yellow/blue plug off the ecu? I only have 2 wires on the back of the alt. when I grounded the wire I did not hear any clicking, I wrapped the wire around a nut checked the warning lights and they werent on.

There any way you could show me any pics so I know I am going about it correctly?

https://www.rx7club.com/attachment.p...7&d=1246899020

I def see the black wire with the white stripe and the other is a white wire with a black stripe, then it goes to a plug then 2 wires on the other side of the plug go into the plug on the back of the alt, ones black, the other is yellow... not positive if the yellow one has a stripe or not.

So I am guessing my warning light cluster plug needs to be re soldered?

skir2222

Theres a picture for reference

HAILERS

Pull the plug off the CPU.

The plug has a yellow/blue wire that goes to the warning light assy.

Ground that yellow/blue and if the key is on, then the warning lights should light up.

The way things work: There is a relay in the CPU called the alt relay. That relay has a coil that gets power if the key is ON. The ground for that coil comes from the alternators white/black wire.

IF the alt is not turning, then the alt puts a gnd on that white/black wire and the alt relay now pulls in.

The contacts in the relay now come together. One of the contacts goes to gnd. The other contact goes to a yellow/blue wire that goes to the warning light assy and puts a gnd on ALL the light bulbs in the warning light assy to turn 'em on.

I was assuming you were looking at a wiring diagram earlier. I now attach one.

So now you know where the yellow/blue wire is. It's on a plug that attaches to the CPU.

But the question I have is. .......if you put a gnd on the WHITE/BLACK wire of the two wire alt plug, do you hear the alt relay inside the CPU click???? CPU is located just to the left of the drivers left foot area. I can hear this relay pull in from the engine bay myself. If you hear the thing click when you put a gnd on the white/black wire, then pull the plug offf the CPU and put a gnd on the yellow/blue wire. IF the key is ON, then the warning light assy lights will all come on.

If putting a gnd on the yellow/blue does cause all the warning lights to come on, AND you hear the alt relay inside the CPU click when a gnd is put on the white/black wire on the alternators plug, then the problem lies with the alt relay inside the CPU or a cold solder joint where that CPU elect plug connects to the CPU.

Another cause of ALL the warning lights not coming on when the key is put to ON, engine OFF, can be that part of the alt circuit is kaput. The alt may regulate voltage just fine and dandy, but if the circuit the white/black wire goes to inside the alternator regulator has had straight batt voltage put to it and burnt out the circuit...........then the warning lights will not ever ALL come on when the key is put to ON...........ever and ever and ever.

IF you put a gnd on the white/black wire on the alt small two wire plug and you DO HEAR the alt relay click inside the CPU...............then try this. With key to ON, put the small plug back on the alternator. When you do you should hear the alt relay click as you make the connection. But if you do not hear the click as the plug is put on the alternator, and you DID hear the relay click earlier when you had the plug off and put a gnd on the white/black wire.............then the circuit inside the alternator is kaput. Not cause for too much worry if the regulator is regulating as normal. Just lost of all the warning lights coming on when key is put to ON.

HAILERS

The CPU has maybe three elect plugs. The one your looking for is called F-04 and is shown in the jpg I attached earlier. It has seventeen sockets in it and the y/l wire is near the middle top row. See that jpg for it.

skir2222

Thank you very much hailers, I really appreciate it! When I ground the W/B wire I do not hear any type of clicking at all.

HAILERS

In that case.......I'd find the CPU which is to the left of your left foot in the car. It has maybe three elect plugs on it. Find the one I described earlier. The one that has the Yellow/Blue wire on it's top row near the middle of that plug. Plug off the CPU by the way.

Now key to ON. Jumper that yellow/blue to a ground point/chassis. All the warning lights should come on. IF so, then it sounds like the alt relay in the CPU went south. Before I bought another *board* for the CPU, I'd ohm out the WHITE/black wire from the alternators small plug to it's other end at the CPU plug.

Do you know if your instrument cluster hass a SHIFT UP LIGHT???? With the key to ON, does this light light up??? Have the plug on the alternator and all other plugs like on the CPU attached when looking for this. I'm curious as to if this light is on/off with key ON, engine OFF>

Again, althought the ALL the warning lights should come on with key ON, engine OFF, it does not mean there is anything really seriously wrong with the alternator. Especially if the alt is putting out 13.5 to 14.2 vdc with engine running. There is a *problem* with the warning circuit, but nothing seriously wrong right now.

skir2222

Update... my battery seemed to completely die, I tried hooking up my charger and setting it to boost and didnt charge the battery at all.

So I took the battery out of my FD, charged it, threw it in there and now it fires right up.

Last night before my battery died I went out for a drive, under boost it would hesitate/load up and different rpm points, it never did this before(this happened right after I got gas so I thought I got some bad gas). Spoke to the shop that fixed my car and said it could be due to the bad battery not supplying enough current and to check the battery with my DMM and see if it has atleast 14.7 if not I have a problem with my charging system.

After I get this sorted out I will move onto grounding the Y/B wire.

skir2222

Tested the alt 13.8 on first start, drove it 12.9, shut it off and turned the car back on now its at 12.4-12.5

On the first drive it did not hesitate till after 10min then it started doing it again.

I guess its not supplying enough current due to a bad alt.

HAILERS

Go out to your car. Start it up. Then after it warms up a bit, rev the engine quickly to say four or five grand and let it return to idle. Then check the output of the alt...either at the alt or at the battery posts. See if it now is putting out what you saw the first time i.e 13.8 or so.

IF it now is putting out, then I'd say the regulator has gone in the alternator. The reason it might be putting out when you quickly rev it, is that it is *self exciting* itself thru residue magnatisem in the rotor assy,.

Another thing out of the FSM, is to idle the engine and backprobe the WHITE/black wire with it on the alternator. It should be showing 2-3vdc. If showing something radically different........bad regulator.

Also with the plug off the alt, engine OFF and key ON, then both black/white and white/black should show approx batt voltage. Shows both Meter and Engine fuse are good. Engine fuse we know is good cause the car starts and runs. Meter fuse is probably good cause the tach/gauges work. I'd look anyway.

But whatever you do, do the rev the engine up quickly to five/six grand and return to idle and check the output at the Battery or alt.

Next time you check the voltage and it reads low, just up the revs to anywhere above 1000 rpm and see if the voltage goes up or not. Worth doing and thinking about.

HAILERS

If you have a series four and put a series five alt on it, then pay attention to the jpg attached.

If you look straight into the jack of the alternator with the plug off, the terminal to the right should get the series four WHITE/black wire and this is the wire that causes the warning lights to come on plus other features.

The terminal to the left should have a constant 24/7 supply of batt power. Where and how you get that 24/7 is up to you. Some just run a small wire from the large output wire of the alt. The stk series five get power from the EGI fuse in the engine bay fuse box.

The switched BLACK/white wire of the stk series four alt plug should not be used for power to the left terminal.

When looking into the jack of the alternator, you want the pay attention to where the keyway is located on the jack. The keyway is .........shown in my jpg attached. IT's the female *notch*.

skir2222

So your saying I should pull the B/W wire off, and run a new wire from the plug to a 24*7 pwr source correct?

HAILERS

That's the way it should have been done in the first place. Yes. BUT it'd be interesting if you did the other things I mentioned.

I believe if you put the black/white wire on the alt instead of a wire with power on it 24hrs a day/seven days a week, what will happen is that the batt will discharge when the key is put to OFF and the cars not operating. Takes some time to discharge. I DON'T thing this wire is the cause of your charging problems right now. I think the voltage regulator inside the series five alt has taken a dump.

skir2222

Ok HAILERS, I did the test how you described it, now with the car off 12.4V, car running 14.4-14.7V. Maybe my old batt went south from sitting so long?

So I guess I should re route that one wire?

zoomy942

iTrader: (2)

not to highjack this thread but i had a question about those lights too.

Mine light up when the key is in and im about to start the car, but once im on, none of them come on for the doors or brake light of anything. the clock doesnt work either. I wasnt sure what it could be since they all come on fine when im starting the car.

HAILERS

Cold solder joints at where the electrical plug attaches to the Warning light unit. Have someone reflow the solder there. This is in the FAQ thread.

skir2222

Hailers, When I turn my key to the on position my shift up light does not come on, however sometimes when I am driving it will decide to work. When my shift up light does work I will get a hesitation at random rpm points, lets say it happens at 4k rpms under half throttle it will act like its getting loaded up then take off and pull super hard. It will act somewhat like that at any rpm when the shift light works but only when I am accelerating.

Now when the shift light doesn't work, my FC runs perfect, idles perfect, revs very clean and pulls very hard.

I have done a tune up, timing and adjusted the tps. One problem I am having is...
MY TPS WILL NOT READ PAST 2000OHMS!!!

I set it to 1k ohms, slowly open the throttle, DMM reads to almost 2000OHMS then loses signal.

skir2222

Hailers, My idiot lights plug wasnt connected with the lights, also I grounded the Y/L wire and that lite up my shift light.

My idiot lights do work now, but not in the correct fashion... The fuel light is connected to my e brake somehow, the brake light stays on, and seatbelt light stays on.

Clock only works when I close my doors, and the only light that comes on when I start the car is the charging light till it warms up then the lights I just mentioned stay on.

skir2222

Hmm only my charging light and clock work as of now, the others refuse to come on.