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Topic: 20th anni a9l swap  (Read 1837 times) previous topic - next topic

20th anni a9l swap

Hey Guys

I'm at that point in the build where its wiring time

1987 cougar 20th anni

89 engine 5.0, t5 and a9l computer, mass air

I've been searching and reading and reading and searching for info on how to wire it up so pin 30 and 46 are cool with each other

the closest I've come to figuring it out is

How to kill, repair and not kill again an A9L in an 88 and possibly others  by CougarSE

memory seat module by james cassity

and some other guys on the mustang forums

a lot of help and info from facebook and instagram

i know i have no voltage to pin 30 when in run or crank so i can get away with not doing any wiring at all but would love everything to work like it could have been stock

i traced the wires out on a physical harness ( 87 cougar ls auto)  from ecu to end points for both pins

My plan was to cut the brown white wire (30) at the ignition switch, bypass it and wire them in parallel with the clutch and ngs , then return them to pin (46)

i was going to splice the red  blue wire between the ignition switch and nss switch wiring and run them to the other clutch switch  and connect them to the white pink (ngs) to complete the circuit for starting.

in my head and spare harness ( cougar ls 5.0 auto)  it was kinda making sense till i got in my car and noticed the memory seat wiring plug had an extra wire instead of ending at the plug , now i am lost.....

someone please steer me in the right direction , ill read anything as long as it will work

my other option was to cut the brown white wire (30) just as it gets into the car before it splits into two leaving the brown white wire connected to the ignition and power seat plug. and add the clutch/ngs wiring at that point


lost lost lost

home made diagram was for me to see it as i was tracing and to kinda help maybe someone else has done this before


Re: 20th anni a9l swap

Reply #1
Where oh where do we get the ground from?
This area of wiring you are in has always been confusing.
Your diagram does not have the ECU killing mistake in it.

Some ECUs want to have ground on pin 30 when the transmission is in neutral or the clutch pedal is pushed in.
I think it is used for idle control with no transmission load on the engine.
The ground comes from the starter relay. When you are not cranking the engine and the trans is in neutral or the clutch is pushed in, the circuit to the relay is at ground. This is because the other side of the relay coil is grounded.

Some cars use pin 46 for the pin 30 ground. Pin 46 is the ECU signal return circuit for various sensors. If you wind up with pin 46 and the starter relay circuit tied together you blow out the sig rtn printed circuit in the ECU when you crank the engine.
The starter relay circuit goes to 12v with the ignition switch in start.

Posting a 93 Mustang pic where they use the starter relay ground for auto trans and pin46 for manual trans.

Re: 20th anni a9l swap

Reply #2
The memory seat uses the starter relay ground so you cannot select a seat setting with the transmission engaged.
You got to be in park, neutral or have the clutch pushed in.
Wouldn't want a short person to accidently move the seat back so they couldn't reach the pedals while tooling down the highway at 80 MPH.

Re: 20th anni a9l swap

Reply #3
i know i have no voltage to pin 30 when in run or crank so i can get away with not doing any wiring at all but would love everything to work like it could have been stock
No voltage on pin 30 in crank agrees with the 87 EVTM. There is no BR/W wire from the ignition switch to pin 30. In fact pin 30 is not shown at all on the ECU.
Your drawing agrees with the 88 EVTM. BR/W wire from the ignition switch to pin 30. Here you will have 12v on pin 30 while cranking.

Quote
i traced the wires out on a physical harness ( 87 cougar ls auto)  from ecu to end points for both pins

My plan was to cut the brown white wire (30) at the ignition switch, bypass it and wire them in parallel with the clutch and ngs , then return them to pin (46)

i was going to splice the red  blue wire between the ignition switch and nss switch wiring and run them to the other clutch switch  and connect them to the white pink (ngs) to complete the circuit for starting.
  Can't wrap my head around all this. Are you planning to use the spare harness or modify the one in the car?

The "other" clutch switch is to put the cruise control in "stand by" mode. The same as pushing the brake pedal does.  The starter switch is N/O, closes when pedal is pushed. The cruise switch is N/C, opens when pedal is pushed.

Bottom line is, don't hook anything to pin 46 that can have a voltage on it. This is the logic ground for the ECU electronics.
Like anytime you hook voltage to ground, something has got to blow. In this case it won't be a fuse or fuse link it will be the ECU.

Re: 20th anni a9l swap

Reply #4
Does your T5 have a neutral switch? The Turbo Coupe manual trans EVTMs only show the clutch switch. 


Re: 20th anni a9l swap

Reply #5
Hey thanks for getting back to me

i plan on using the harness in the car to mod into mass air

i was wrong , i think i only tested for for voltage at pin 46 not 30 while cranking

i did run the a9l in my old 87 cougar with auto trans and h.o mass swap with no problems

yes the t5 has a ngs on the top of it 


i know the only differences in the car harness and spare harness are 20th anni options and ls options

this is what i was thinking .... how does it look ???


this way pin 30 never touches ignition just two switches and back to 46

still using clutch pedal for start

and seat memory still gets signal from clutch ?

i see two switch plugs on the clutch pedal i guess one for start and one for idle/no load,,, i dont have the cruise switch on my pedals

Re: 20th anni a9l swap

Reply #6
Yes pin 46 looks safe the way you have diagramed it.
To select a memory seat position you will need, key-on and push the clutch. Since you don't have the NSS switch that is closed in park.
I can't find any diagrams that have two clutch switches that close when the pedal is pushed.
One is for the cruise and it opens when the clutch is pushed.
What car are your pedals from?

Re: 20th anni a9l swap

Reply #7
the pedals are out of an 89 mustang

the switch i have has two plugs like the turbo coupe but have to add them to my harness

one plug for the start neutral 

one plug for ecu pin 30 parallel with ngs connecting pin 46 

Re: 20th anni a9l swap

Reply #8
I think you should check that switch with an ohmeter to see if they open and close together. Or is one open when the other is closed.

Re: 20th anni a9l swap

Reply #9
This will also work.
 It gives you two ways to start and use the memory seat if one of the switches fails.
It satisfies the pin 30 requirements.

Re: 20th anni a9l swap

Reply #10
just checked the switch , both plugs are open till the pedal is pressed  then they close, and they share no electrical connection


Re: 20th anni a9l swap

Reply #11
You would assume by the age of 88 I would have learned not to assume shit.
The Clutch cruise control "safety cancel switch" is a separate unit.
Base part number: 9F645
 

Re: 20th anni a9l swap

Reply #12
my clutch pedals didnt come with that one , so i figured i would just not use one. if i needed to turn it off i would tap the brake or use the steering switch

Re: 20th anni a9l swap

Reply #13
hey softtouch


thanks for all your help , i just got to the wiring today ,only -7C in the garage up here in Ontario Canada

pin 30 did have voltage on crank.

i did all the pin changes for the mass air and h.o swap

i ended up wiring my clutch switch plug #1 in place of the old NSS (auto) so it will only start with clutch in.

i cut pin 30 at the ecu harness plug and wired in parallel with clutch plug #2 and the NGS on top the t5 and connected them to pin 46

it now starts, idles and drops idle a little when in neutral or clutch is presses like its suppose to

Sorry it took so long to get back and thank you






Re: 20th anni a9l swap

Reply #14
Glad it all worked out.