ECU pig tail plug... What is it?

[Reign_Maker]

Pulled my pre-89 m/t ECU out to install my AEM, and I noticed something... I has a pig tail plug coming off of it... Whatis that for? Because I dont have any extra plugs under there... When I installed the AEM, all the plugs were used... So I was wondering, is this for if you have an auto tranny, the tranny's comp plugs into it?

 

[CRE]

A pic would help. How many pins? It's not for the HAC is it?

 

[Reign_Maker]

 

[AF1JZ]

Well, it's a m/t ecu. So, it shouldn't have anything for a hookup to the auto tranny. I dunno Jake. Maybe a test port or something?

 

[Reign_Maker]

Well, see, the sad thing is, its been SOOOOOO long since I pulled my harness out, i dunno if anything was even plugged to it... Like I said, when I plugged the harness back in to all the plugs and the AEM I didnt have any left over plugs, so I dunno what the hell it is...

Traction control maybe?

 

[tissimo]

not sure what they are on the 7m, but my 1jz was a a couple wires for my tps.. but didn't need w/ my aem, works fine without them..

 

[Reign_Maker]

So do I have some odd never before seen ECU here? Someone HAS to know what that plug is for... How wierd is this? I just wanna make sure its not someting my AEM will need... but like I said, i cant find anything that plugged into it... Its been so long, for all I know, NOTHING was plugged into it, lol...

 

[Doward]

LOL, I think it goes to the pre '89 HAC - I'll check tomorrow (it's dark out, and I'm too lazy to do it tonight )

 

[Reign_Maker]

My hac is plugged in... so, not the hac... *you mean the hac sensor right?*

 

[Doward]

Yep. hang on, I have my wiring harness here...

Ok, I can tell you that the plug that goes into it, only has 3 wires coming out - a purple, a red with green stripe (and black dots down it) and a red with a yellow stripe (again with the black dots).

I'm almost positive it's the wiring interface between the HAC sensor and the TCCS, though....

 

[Reign_Maker]

The pig tail has five wires... white, yellow, red, black and green...

 

[Doward]

http://members.cox.net/~doward/jakeswires.JPG

Talking about that plug in, yes?

 

[bigaaron]

It's just the flying lead.

 

[zoppii]

My 88 has the same. 5 wires going out of the ECU and 3 going to the wire harness as in Doward's pictures

 

[Doward]

So what does it fly to?

 

[Reign_Maker]

Nope, not it... The hac sensor mounts under the glove box... I have one of those... Its just wierd...

 

[bigaaron]

If I remember correctly one wire goes to the tps, I forget what the other ones do. I'll look at my 88 tsrm later tonight.

 

[Doward]

Jake, on my '88, the lead that comes out of my ECU, goes to the plug I am holding in my hand in that picture (click the link)

 

[bigaaron]

I think the other wires were abs related maybe.

 

[zoppii]

I have ABS and I still only have 3 wires going out and 5 going in.