88 GXL
Symptoms
Both left and right the little "click" noises can be heard, but no blinkers outside or on instrument cluster . . .
I tired a switch set from a 91 and got a weird buzizng from some relay infront of the radiator, but no thing worked.

Any ideas?
CPU?

 

any help would be great id like to know this doesnt mean tracing through the entire harness

 

Tried another S4 switch, this time no weird buzzing, turn signal clicking noise works but the turn signals them selves do not work, nor do the hazards . . . Body computer?

 

may sound stupid but have you checked fuses?

 

got too dark pulling fuses tomorrow to double check, i know its not the CPU now as well . . .

 

not a fuse . . .

 

you cant use the 91 switch unless you rewire the connector, which to you you need wiring diagrams from both years. i say its the switch , get another s4 and youll be golden

 

tired another s4 already

 

the S5 switch may have overloaded the relay in front of the radiator

 

didnt work even before i tried that one.

 

so when you're using an S4 switch with an S4 harness, all you is the turn signal clicking noise. correct?

may sound like a stupid question, but are the bulbs any good? when did they last work? the wires and connectors are in good shape and plugged in?

 

everything is gravy, i think the harness is fucked somewhere, but how it happened out of nowhere i'll never know

 

why did you change switches? same problem?

 

yep, and CPUS both from s4s

 

so i'm officially lost with this, since the switches, fuses and CPU's checked out good, HELP!!!!!!!

 

The Turn signal circuit board and plug is the same in all FC and FD CPUs regardless of series.

However the turn signal switches are not.

Buzzing up under the hood by the radiator is the headlight highbeam relay. That indicates the wrong turn switch is being used with the wrong light switch harness. The only relays for the turn signals are on the turn signal circuit board in the bottom of the CPU.

S4 turn switches must only be used with a S4 headlight switch harness. S5 turn switches must only be used with a S5 headlight switch harness.

If you have mixed and matched, you will get that buzzing.

You have not said if the hazard lights work. They also use the CPU turn signal board. If the hazard lights work fine, but the turn signals do not, then you have either bad inputs to the CPU or a bad turn signal switch or a wiring issue between the turn signal switch and the CPU.

 

i have the same issue with my S5....my hazard work..but only right turn dont'work..and i can hear fast click noise when i turn it on...

 

that indicates a bad bulb on the right side, or a bad turn signal flasher board (which I do have available on my webstore).

 

hazards are dead too, the CPU works fine, tested it in another S4 same with the switches, fuses are good too, it has to be in the wiring but where? i feel a gigantic headache coming . . .

 

Hazards dead too indicates no power or no ground is getting to the CPU flasher board.

Do you have power and ground there? At the bottom plug of the CPU???

 

I dont have a multimeter to check, but when you activate the turn signal left or right you can hear the turn "ticking" noise coming from the CPU

 

Okay, then it should do the same for when you have the hazards on.

If that is the case, then it is a wiring issue between the CPU and the lights, or again a bad CPU.

You said you tested another CPU in there and it did the same thing???

 

Correct, another S4 GXL CPU, exact same results, and to be sure i tried that CPU in the other car and it was fine.
edit: just went to double check, does not tick when hazards are pushed.

 

Well . . .
Im basically swapping everything from my '91 A-Package coupe to this '88GXL with the signal problem, would it be worth it to swap body harnesses as well? That way i can refresh all grounds and familiarize myself with the wiring? I plan on using the S5 Engine, Trans, driveshaft, wiring harness and ECU entire black interior (minus those pesky auto belts) Doors etc . . .
So swap the body harness too? use the S5 systems?
Can i use the S5 NA tranny mount on the S4 NA?

 

no suggestions?