MTRfc

alright basically i pretty much have my headache almost completely nailed.

long story short, swapped s5 jdm motor into s4 usdm 87 fc. got just about everything to play nice.

trying now to figure out the turn signals for a while. i believe i've narrowed the problem down to a ground problem.

if anyone could provide perhaps an edited pic of the fsm where it shows the proper pins to check on the body harness to the cpu/flasher and the corresponding colors they should be i would really appreciate it.

i need to know which pins are supposed to be the grounds on it so i can run through the wiring harness and make sure they are grounding properly. its not getting a full ground where the harness plugs to the cpu. that is where my problem i believe is.

thanks guys.

if possible email an edited pic to akamaverick87@aol.com

MTRfc

oh and before anyone suggests checking the fuses they're fine and the relay is not clicking and the lights on the hazards and the turn signals dont light up...

Icemark

The ground for the tail lights are at the tail lights, the ground for the front bumper lights is underhood.

So the problem is probably not grounds... in fact you are probably wasting your time even looking at the grounds unless you removed the fuse box / front harness. And even then really easy to check and see if the black wire at the turn signal/hazard plug of the CPU has ground on it... if it does your problem is not a missing ground.

Since the hazard light switch does not work, that also pretty much rules out the turn signal switch, and points to the CPU.

Is the turn signal/hazard plug, plugged into the bottom of the CPU?

If it is plugged in, does the Black/Blue have 12 volts on it? If it does not, either the fuse is blown, or the underhood 60 amp BTN fuse is.


so at that bottom CPU plug:
If both the black wire has ground and the black/blue has 12 volts, then if you ground the Light green (no sub color) is grounded, then the turn signals should flash, and the Green/White and Green/Black coming out of the bottom plug on that CPU should be flashing 12 volts+... NOT GROUND.

MTRfc

the green/white and green/black are reading pretty much 0. i did everything else that you suggested. what next?

HAILERS

Pull the plug off the CPU that is shown in the jpg.

Put the turn lever to right or left and see if the G/R or G/Y wire has batt power or not. Key on.

No power? See if the TURN AND HAZARD fuses are good.

Fuses good? Then go pull the plug off the turn signal assy, CR-03, and see if the BR wire has batt power on it. CR-03 is the dimmer switches plug.

No power there? Then pull the plug called fc-02 apart and see if the BR wire on the plug has power or not. FC-02 is the connector b/t the Front harness and the cluster harness. Might be BLUE in color...maybe. Seventeen pin/socket plug.

Piece of cake.

MTRfc

im gonna try that right now and ill post up what i figure out. crossing my fingers...

MTRfc

alright question... icemark i tried what you were talking about but got no power from the green/white and green/black wires when i grounded the green wire. the signals did not flash. the fuses appear good. have removed them and checked them several times. the green/white and green/black wires were showing almost literally 0 volts...what does that tell me? the switch is bad for the turn signals? i need to rewire those wires? i have no clue.

and hailers im workin out what you were telling me to do.

Icemark

Again, the Black/Blue... you didn't test the black/blue. Does it have 12volts+ always on it?

HAILERS

In that jpg I attached in post #5, it shows the B/L or black blue wire coming out of where it shows the numbers 1(9). That 1(9) comes from the Hazard fuse I believe. So he wants you to make sure that it has batt power.

The 1 (9) that I write of isn't printed exactly in that form. The 9 has a circle around it in the jpg.

That is the power that actually powers up the right/left turn bulbs, but I suggested checking the G/R and G/Y wires because they are what makes the flasher unit *flash*/work and make the contacts make/break. I went that path because you didn't mention any clicking of the flasher unit when you selected right or left turn.

Check all three wires. Black/Blue, G/R and G/Y.

No power on the black/blue means there is no power coming from the Hazard fuse and if no power is seen on the G/R or G/Y when you select right/left turn, then that means your not getting any power from the Turn fuse. Either because a connector is unplugged or fuse blown or ?????? something else that I can't think of right now.

MTRfc

i checked the black/blue as you said icemark. that what i was saying in my last post. i did try exactly what you were suggesting and i still got no flashing.

the black/blue does have power with key on and key off.

the g/r and g/y do not have any power with key on and key off.

what i was thinking is since the wires (g/r and g/y) go from the turn signal switch to the cpu, i could try running those straight to the cpu and seeing if that works. the only thing i could think of was maybe somewhere in the wiring they got screwed up or something.

thoughts? another route you can think of? fuses in the box are fine as is the btn under the hood.

Icemark

Think you are missing what I am asking. Just to make sure. You are testing these at the plug at the bottom of the CPU... correct?

Great, the black/blue has 12 volts all the time. This rules out the fuse being blown. See, step by step.

If we ground the Light Green, while the black/blue has 12 volts on it, and the Black has ground on it, and nothing happens, either the plug is not plugged into the CPU or the CPU flasher board is bad.

See the light Green wire is from the Hazard switch in the wiper switch as well as the security system. So when we ground it, it is just like if the alarm grounded the wire or triggered the wire and the turn signals should all flash. If it doesn't then either there is not ground on the black wire (which you said you tested), or there is not 12 volts+ on the Black/Blue (which you said you tested) or the CPU is not plugged in (which we should be able to see since we should be testing the wires at the CPU), or the flasher circuit board is bad. Even if all the bulbs were burnt out (two dash bulbs, one light in the hazard switch, and 4 corners) you should still hear and feel the CPU flashing when we have ground on the Black and the light green wires and 12 volts + on the black/blue wire.

So do not re-wire anything. Rewiring is a sure way to get to have electrical gremlins in the future.

MTRfc

alrighty. tomorrow when it is daylight out, i will double check once more the black and the black/blue wire and make extra certain that they are juiced.

now to make sure im perfectly clear, when you ground the light green wire (when the black and black/blue wires are showing 12 volts) the signals should come on...

if that is the correct, it did not work yesterday. i would assume at that point that the cpu is bad.

the only other thought that comes to mind is the other part of the cpu which has the 12 or 16 pin (at the top of the cpu). could it have anything at all to do with that plug? or does that not make any difference and even if that is not plugged in it should still work?

either way i did try it with and without that plug being plugged in and still no dice. if all this is correct, then it sounds like i need another cpu (at least for the flasher board inside it). maybe it burned out internally. i haven't yet opened them up to look but the tips look absolutely fine.

i will try all the cpu's i have and make sure that they are all not working before getting one of those.

i only suggested re-wiring because i do have another set of the same plugs and if there was a way for me to test the cpus with those wires done up individually outside the car then i'd know for sure that it was a wiring problem and not the cpu itself. does that make sense?

thanks again.

MTRfc

oh and please let me know if that bigger plug on the cpu (the 12 or 16 pin one) absolutely must be plugged in, in order for the system to work. thanks! it would make it easier to work on if it doesn't have to be plugged in. (the plug for some reason is a pain the you-know-what to take on and off)

HAILERS

You'd KNOW if it was a CPU problem or not if you'd just pull the plug off that's shown in the jpg below and see if there is batt voltage on the B/L wire, and then see if there is power on the G/Y or G/R wire when you select right or left turn.

It's the wires in the Plug your checking , not the jack on the CPU itself.

Upper plug has zip to do with the turn signals. Remove it if you want.

Make sure you have the right CPU installed in your car. In other words not one for another series car. But do the voltage checks above first.

In case I got it wrong earlier, the B/L wire is from the HAZARD fuse and the other two are fed from the TURN fuse via some connectors inbetween.

Icemark

No the black wire should have ground on it at all times! Just like the Black/Blue should have 12volts+ on it... At all Times. If the black has 12 volts on it, nothing will happen (and more than likely you don't have the dash harness grounded).

Do you know how to use a meter or even a [shudder] test light? Set the meter for 20+ DC volts, put the red lead of the meter on the black/blue wire and ground the black lead of the meter. The meter should display 12+ volts. Now put the black lead of the meter on the black lead of the bottom plug of the CPU... again it should read 12+ volts. If you move the red lead of the meter to another 12 volt + source (cig lighter for example) and still have the black lead of your meter hooked on the black wire of the CPU's bottom 7 pin plug, it should still read 12+ volts when the key is on.

But if we put the red wire of our meter on the black wire of the 7 pin CPU plug, and the black lead of our meter on ground, and we are seeing 12+ volts, then you don't have the dash harness grounded.

Well, again, I think you are not testing correctly or you are having trouble posting what you are really doing. Because you didn't say that you tested the Black/blue until I posted twice about it, and now you are saying the black has 12 volts on it.
That plug does not do anything with the turn signals or hazard lights. It deals with door buzzers, key buzzers and lights, the Horn, the high beam on some models, etc. Don't even mess with it.

Again, the tests I have given you ONLY work with the CPU plugged in and are meaningless and a waste of time with it unplugged. Now Hailers tests, you can do unplugged, but that just confirms if the switch is working or has power. Since the hazards don't work, I don't even care about the switch, but that would be the next step to check once we confirmed the CPU's flasher board works.
Be careful to only try the flasher plug. It is the only part of the CPU that is wired and compatible through all years of FC and FD production. The main harnesses and brake light harnesses vary between year and sub model. If you have a 87 GXL, the only two CPU's that will work in that car are the FB01 and FB05 CPUs.

Dude...[Mark, shakes his head in frustration] if you are testing at the CPU, it doesn't matter what the wiring is like in the car. So NO... re-wiring is just about the last thing you even want to consider until you can make the CPU even work. If you can't even make the CPU's flasher circuit work, how the heck can you even consider changing wiring in the car. We are talking about three wires here. Power, Ground, and Trigger. Why the funk would we even consider re-wiring anything if you can't figure out three wires.

HAILERS

As some form of exercise, I just did what I suggested above. I left this laptop at 1:20pm ...went to the garage......picked up a meter, lifted the garage door and approached a car. Unscrewed the nut holding the CPU on the chassis........unplugged the seven socket connector off the CPU........put the meters neg lead on the threads of a bolt on the foot bulkhead.........put the positive lead on the black/blue........got 12vdc.......put the meter on the G/R and put the signal lever down.....got 12vdc........put the meter on the G/Y and the signal lever up.......got 12vdc.

Shoulda used the Black wire in that plug for the gnd instead of the bolt I mentioned to prove the Black wire in the plug is indeed going to gnd. Big dealeo.

That should tell you if the signal is getting to the CPU and if there is batt voltage getting to the B/L wire to feed the light bulbs thru the flasher.

I got thru at 1:27. Does not take long to figure it out. Does not count the time I need to put the CPU back in place.

MTRfc

i apologize icemark. using a test light i checked the black and black/blue. when grounded (to a bolt) they both light up, but when using one end to the black and the other to the black/blue which is what im understanding i should do, it does not light up. so my problem sounds like a bad ground. does that sound correct?

HAILERS

That ground is ground point #10 as shown in the online wiring diagrams. Well, the other end of that Black wire is at ground point #10.

As shown in the attached jpg, ground point ten is located in front of the instrument cluster. You have to remove the instrument cluster to see it. Front meant fwd of the instrument cluster. It's bolted to the structure with one bolt if memory serves. Why or how that one wire gnd could come loose is a mystery. As the first jpg shows, there is no connector b/t the plug and the ground point 10.

MTRfc

alright so doing what icemark said with a light tester:

hooked up black wire of light tester to ground and red wire of light tester to black wire. light on.

hooked up black end of light to ground and red wired of light to black/blue wire. light on.

hooked up black end of light to black wire and red wire of light to black/blue. no light.

if i understand (which at this point i swear i did) that would mean that it is not grounded properly because the light should pop up when i have the black wire of the light on the black wire of the plug and the red wire of the light to the black/blue wire.

did i get this right?

if so what should i do next?

MTRfc

anything guys?

MTRfc

still waitin on a response.

MTRfc

seriously need to finish this up guys...please...i have a big meet i want to get the car to in 2 days...on sat night!

MTRfc

what the freakin crap...i think i may have found the culprit...and if so a shop probably screwed me over completely by trying to wire it differently...i want to kill them...


it may be possible that i have s5 assembly's in my gauge surround instead of the stock s4 ones that i should have...

if what i've been reading is correct then that would cause a problem with turn signals not working correctly right?

if anyone has got some part numbers i can ref i will freakin love you and let me know if this could be indeed the problem...

ugghh...freakin rotary shops that dont know what the hell they're doing.

MTRfc

dammit..alright so i haven't heard from anyone but hopefully if someone reads this...

i replaced the turn signal assembly itself in the gauge cluster...

i suspect that either the switch itself was bad or it may have been an s5 if what i've heard is true about s4 and s5 parts not really being compatible.

either way great news:
the turn signals on each side come on. they dont flash on and off yet, but i got them to at least come on....and that's on both sides.

one step closer.

now i just need to find a hazard switch for an s4 and see if that fixes the rest...im praying it does...looking at the schematics tonight to see if the hazards and turn signal switch are linked in sequence (i assume they are) and that may explain a few things.

if anyone's got info please lemme know!