71 HO Wire Harness.
 

I'm in the process of resurrecting a 71 455 HO car that's been sitting since the 80's. There are some parts and pieces missing. The car is a 4spd no AC. I'm trying to identify where this plug goes on the engine harness? The part it plugs in to may be gone. Thanks for any help.

I'm rusty and without a wiring diagram in front of me but I want to say it's the connector that came off the TCS solenoid harness waiting for the jumper from an auto transmission. So it wouldn't be connected to anything on your 4 spd car

Pretty much what I told Paul but there is a spring loaded ball switch that threads into the drivers side of a manual transmission that is part of the TCS system on a stick car as well.
Many times people would just remove this switch and put a plug in it but it was there from the factory.

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Ah, thanks for the info. my only experience with the TCS setup is on my 71 Lemans auto car. All my 4 speed cars were 68/69 and didn't have that stuff on them then.

High blower/ac compressor jumper feed wire , big single wire goes to back of alternator, smaller wire goes to compressor. Another ac harness necessary.

Well according to Ames I have an AC harness on my non AC car from the factory. Can anyone confirm this set up up? My car has the 30A fuse holder by the alternator, but the new harness I received from Ames does not. Was this common practice to have the incorrect harness? Thanks for your input.

Some interior harnesses (at least 70 Firebird) had extra circuits that were taped up if not used.

I'd try checking continuity from the fuse end and see where the other end is? And where it might go?

Do you have the PHS? What does it show for electrical options?

:)

Yes I have the PHS and the build sheet, everything that should be there is there for options. The only parts I think I might be missing is a carb idle solenoid or TCS set up.

No ac harnesses were never installed on non ac cars. Someone did some changes. It is a 50 y/o car and unless you owned it since new and documented everything that was ever done, you can't say it wasn't modified incorrectly. The 30 amp fuse is the dead giveaway, ac only high blower relay feed.

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Ron we have been investigating this issue tonight. Here is a photo of my original paint 71 4 speed Judge. It is a non/AC car with no significant options and like many others I have seen, has the in line alternator fuse factory installed. I will also attach a photo of the May of 71 parts book reflecting that the engine harness is the same for all 1971 455 HO A body cars. It is the same regardless of transmission and whether it is equipped with air conditioning or not.https://uploads.tapatalk-cdn.com/201...28a704f8ec.jpg



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Jeff,

I believe it is listed as HO only is because of the routing and length of wires. All non-ho cars the starter wiring harness and the + battery cable were routed between cylinder 5 & 7 in the tube. All ho cars was routed down the front of the engine due to fact ho cars did not use the tube because of the interference of the exhaust manifolds ( I am certain this is just review for you). Why a high blower relay 30 amp fuse holder that doesn't go anywhere is beyond me. I do not have any original 71 A-body HO cars to check. It is not TCS; there is no TCS solenoid on a 71 HO, uses the TVV system similar to 68-69 cars.

What is a TVV system?

The new harness came with a plug that is about the length of the oil pressure sending unit wire, it's black with an orange tracer. The harness I removed doesn't have this connector, just the unused plug for the AC.

I did a little more digging and found 2 more unrestoed 71 Judges, a Lucy blue one and the Orbit Orange Judge. Including Uncle Judge's (Jeff's) that's 3 non AC original cars that have the fuse holder by the alternator. The car Ames has at it's head quarters also has the fuse holder. Although my car has been messed with, I believe it to be the original harness.

TVV is the acronym for the thermal vacuum valve; uses engine temperature, the vacuum valve on the right front of the intake, the ported vacuum orifice on the carb and a manifold vacuum port to manipulate the distributor advance during various engine operating modes. TCS system on all other applications uses the electrically operated solenoid, temp sensor and manifold vacuum to perform the same task.

The black/orange wire & plug is for the turbo 400 kickdown connector on the left side of trans; may also be used for the tcs switch on the front fork of a manual trans, but I don't have a car on the premises to verify.

All of the above is in the 71 service manual.

I spoke with the harness manufacture today. It appears that the aftermarket AC harness was created from GM harness part number 8904167. There non AC harness was created from that GM harness as well, but with the AC wire components removed, creating a harness that doesn't or didn't exist from GM.

I have examples of 7 original cars without AC that have the fuse holders. 5 71's and 2 72's so far.

And these all have the AC connector that plugs into AC?
(taped up in harness?)


:confused:

From what I have seen the plug is at the back of the engine by the dist. Uncle Judge's car had the plug hanging in the metal wire loom bracket on the fire wall, but it has the little bracket that look like it attaches to the rear valve cover bolt (valve covers were changed at some point). I'm still trying to gather more info. Here's a picture of the plug. I think there is a separate harness adapter that goes from this plug to the AC compressor. I haven't seen what that harness looks like yet. I'll have to dig up some info on that.

PGG - I can provide another data point. My '71 HO (low option) is also a non-AC car, has the in-line fuse at the 37 amp alternator, and has the passenger side plug attached to a small sheet metal bracket that's then attached to the aft-most valve cover bolt. Appears to be consistent with Jeff's pictures.

Vince

Thanks.