89 Mustang Gt Hatch Electrical... Thanks :)

d.ryan.b · Jun 10, 2015

I couple weeks ago I bought an 89 GT mustang for 800$ from an old lady who's son was in the military...I was told it had a t5 swap from an automatic so the wiring is kind of a mess, my problems are... power windows and lock don't work both sides was able to roll up the windows by jumping the motor... and I cant find my eec test plug either.....also the gas gauge does not work was way past full cant even see the needle it goes so far up but, it runs super strong and has tons of power - and I would like any input anyone has to help me get a handle on all these wires and plugs...was also wondering about the wire with the fuse plugged into it which is under the drivers side kick panel...... there is a whole harness that is clipped behind the stereo along with 2 random plugs curious about those as well... any input would be appreciated the previous owner spent MONEY on the motor & trans - and ruined the wiring.... so for 800 I copped it real quick...

t5 swap- king cobra clutch
trick flow top end kit installed by a shop in Arizona - fox body performance

this is one behind the stereo there are those 2 small ones and 2 bigger ones in the back with another one chopped completely

jrichker · Jun 12, 2015

You have a mess, and the best thing I can help with for long term use is offer you a free set of wiring diagrams for an 89 Mustang. The wire colors and connector shapes are on the diagrams and they will help you determine what's what.

PM me your email address and I will send you a complete Ford Factory 89 Mustang electrical diagram set. The zip file is 2.5 MB and is too big to fit through Stangnet's email gateway.

89 Mustang wiring diagrams zip package–

They are in a zip file format to reduce the size of the package. If you don't have Windows 7 or Windows 8, you’ll need WinZip or other Windows archive tool to extract them from the zip file.. See MajorGeeks.Com - MajorGeeks - Download Freeware and Shareware Computer Utilities for a free download.

The diagrams show the location area and the connectors are drawn to the same shape as those in the car.

You will need the Adobe Acrobat viewer which is also a free download – Adobe Acrobat Reader DC Install for all versions - Adobe Reader download - All versions

The diagnostic connector may have a cover over the end of it...

87-92 power window wiring
Diagrams courtesy of Tmoss & Stang&2birds

modulistic · Jun 16, 2015

ugh, thats a mess. looks to me like someone replaced the entire engine harness from a different year and had to scab the two together to make it run. I am betting he bought the engine/transmission/harness/computer as a whole and swapped it all in... then went bananas with twist splices to get it running. You can see he has some kind of tuner chip hanging out the back of the computer. you will have to figure/verify out what year harnesses you are dealing with before anyone can be much help here. nice heads and intake though.

Chuckman · Jun 16, 2015

the black and gray connectors in the background of the first pic are for the factory amp, not used with aftermarket stereo. i THINK the two in the foreground may be too, looks like whoever did it didnt realize that the amp has its own sub-harness that plugs in between the stereo harness and the dash harness.

that little plug in the 6th pic is the spout connector, basically just bridges those two wires. when you want to adjust timing, it gets unplugged to defeat the ecu's automatic advance, then plugged back in once you get the base timing set.

the three-wire plug in the second to last pic looks like its for the low-fluid sensor on the master cylinder. and its been a while, but i thought the stock m/c's were aluminum?

also while you're in there, separate out those plug wires, wire tying them up like that is a good way for some crosstalk/crossfire to happen.

otherwise, that harness looks well and truly hacked, good luck getting it back together again.

d.ryan.b · Jun 17, 2015

thank you all for your help I have managed to piece together the passenger side and got all power doors and locks working as well as the entire stereo system and al the low fluid lights I.e coolant wiper fluid etc...still having a problem with finding out how to diagnose this cars CEL but everything else is basically put back together thanks to you guys. still got a long way to go but I am getting there thank you once again.... since this thread has helped me with my wiring this should be an easy one for you guys...now ... this damn sunroof....I don't think it is after market but I am having a hell of a time even finding any of the hardware I need for this POS...

jrichker · Jun 17, 2015

Dump the codes: Codes may be present even if the Check Engine Light (CEL) isn't on.

Dumping the computer diagnostic codes on 86-95 Mustangs

Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.

Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.

Here's the way to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

Post the codes you get and I will post 86-93 model 5.0 Mustang specific code definitions and fixes. I do not have a complete listing for 94-95 model 5.0 Mustangs at this time.

Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. On a manual transmission car, be sure to press the clutch to the floor.
Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.

If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and driveablity problems

Some codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off, and clutch (if present) is pressed to the floor, and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

Your 86-88 5.0 won't have a working Check Engine Light, so you'll need a test light.
See AutoZone Part Number: 25886 , $10

Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see Equus Digital Ford Code Reader (3145) Equus - Digital Ford Code Reader (3145It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $22-$36.

d.ryan.b · Jun 17, 2015

problem is It is an 89 with no diagnostics connector look at the 8th pic at the top the is behind the drivers side strut tower were I assume it should be lying, it seems that one was their at one time....strange....

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89 Mustang Gt Hatch Electrical... Thanks :)

d.ryan.b

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jrichker

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modulistic

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Chuckman

GTFO you fat, heavy bastard

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