Below are two different threads related to the bad 240 wiring harness. I thought (mistakenly) that the new (good) harness was in all 1987 cars but apparently it's mid-1987. Does anyone know 1st production date for cars with the new harness?

To confirm: cars with the older bad harness had the grey connector on the firewall - correct?

I understand that the wires on the front left (facing) of the engine are the most prone to failure. Is that also correct?

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posted by pageda on Thu Dec 17 05:54 EST 2009

The replacement harness is #3515364. Look closely at the wires on the engine side and you will see deteriorated insulation and exposed wires. Yes through 87 had the bad wires, the 4 wires at this connector can be replaced by re-routing wires from the connector directly to the alternator or oil pressure sender. It is best to cut the wires at the connector and do not disturb the main harness. Dan
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posted by jfh0jfh on Thu Dec 17 10:25 EST 2009
Thanks Dan. I thought 1986 was the last bad wiring harness but looking through the archives I see "through 1987" or "through mid-1987". I fought with this on 3 older cars and swore never again. It reminds me why I prefer the later cars and I'm going to try to stay 89-up anyway.

OK, so: I understand about the wiring and the deterioration. I didn't know the grey connector was associated with the bad harness. Probably the oil light was staying on and they just cut the two suspect wires. I've respliced them and we'll see how it goes today.

There are two other wires on the block: a large blue/ yellow and a smaller red. The red is the alternator? The other?
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posted by Blue Horse on Mon Mar 3 20:44 EST 2008

I, too, looked at an 87 245 that was for sale a few weeks ago, and it definitely had bad wiring. Didn't think to note the production date though (didn't buy the car either) but I'm sure it was an 87. think the new improved harnesses came out during the 87 model year, so some will have them and some will not, and, as far as I know, all 88s are the late type.
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240s: 2 drivers and some parts cars