Omni GLHS alternator harness replacement

Ran into another issue with the rebuild of glhs 290. I really don't know the history of this vehicle but there is has been modified work done to the car. The car already has a ND alternator installed and the harness is in really bad shape. I found a NOS alternator harness on ebay and purchased from a fella that goes by the name Ralphmonster. For the most part the harness looks the same minus the connections for the alternator. I'm not seeing a connector for the ECT sensor on the new harness. On my old harness it looks like a GM style 2 pin connector. Also on the oil sensor the old harness is a 1 pin connector and the new harness is a 3 pin. Should I got back to the original alternator and what to do about the ect plug? I will provided pics to be show my issues. I really don't want to cut up a brand new 165.00 harness if I don't have to.

The denso alternator is an improvement/upgrade over anything else so I would keep that and make everything else work towards it.

The ECT connector is a metripack 150 series connector and terminals that are readily available from mouser/allied ect. How bad is 'bad' ? What is the intended outcome for appearance/originality ? You can use the harness off of a later EFI car (even a TBI, just add the 2nd HEP connection) and get the molded connector for the denso alternator, with some careful splicing and matching up the other wires it would look 95% original and nobody would be the wiser.

The harness is basically trash, tons of poor butt splice repairs from the PO. It's soak in oil and the wiring is hard and brittle. If I have to modify the harness I will at this point. I'm a Mercedes-Benz master tech so I know my way around wiring and repairs. I'm not looking for a show car, I just want reliability. So do I need to add the wiring for the ECT or just convert the plug? Not really use to these old school connectors on this harness. Still trying to add pics.

I used 0/1 gauge welding cables to make new alternator and starter harness following original harness.
When I moved onto Microsquirt, I bought all new wiring and connectors for all the sensors.

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Originally Posted by tryingbe

I used 0/1 gauge welding cables to make new alternator and starter harness following original harness.
When I moved onto Microsquirt, I bought all new wiring and connectors for all the sensors.

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not a bad idea. I have some ground clamps from my mig welder I can use. still trying to sort the ECT connect. It's hard going off of memory as I leave the car at the dealer and work on it after hours.

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Originally Posted by malloy

not a bad idea. I have some ground clamps from my mig welder I can use. still trying to sort the ECT connect. It's hard going off of memory as I leave the car at the dealer and work on it after hours.

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Engine Coolant Temperature sensor is two wires. One is ground signal from ECU, one is signal to ECU, what are you trying to do?

http://www.minimopar.net/ecu/coolant_temp_se.html
http://www.minimopar.net/ecu/lm-1986-t2.html

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Originally Posted by tryingbe

Engine Coolant Temperature sensor is two wires. One is ground signal from ECU, one is signal to ECU, what are you trying to do?

http://www.minimopar.net/ecu/coolant_temp_se.html
http://www.minimopar.net/ecu/lm-1986-t2.html

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what i'm trying to figure out is the NOS alternator harness I purchased does not have an ECT sensor connector. I'm the item description it said the harness does apply to the 86 omni GLHS.

This is the harness I purchased.

https://www.ebay.com/itm/254247893757

have you got the manuals for your car .. with the wiring diagrams ?

(edit Q - is the harness the same length as your original or is it significantly longer?)

you'll have to go to the diagrams and trace your harness back up from the connectors where it attaches to the compartment harness behind the battery
identify which wires should be the temp sensor and trace those pin locations & their wires in your new harness
find where they end and simply splice on the plug you need

that red single pin connector is odd
oil switch plug looks odd
the regular right angled temp gauge connector seems missing ..is that the red one ?? is the wire purple .. it usually is

but yeah it's different to be sure ..but you have enough you should be able to work up a really nice front engine harness with a little effort

sure plug N play would have been nice but you can still make this work

I hope you're not paying the dealer to do this .. 'cause it's to simple to be paying for , it's just straight bench time .. with a book on your knee.. so to say

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Originally Posted by Dr. Johny Dodge

have you got the manuals for your car .. with the wiring diagrams ?

(edit Q - is the harness the same length as your original or is it significantly longer?)

you'll have to go to the diagrams and trace your harness back up from the connectors where it attaches to the compartment harness behind the battery
identify which wires should be the temp sensor and trace those pin locations & their wires in your new harness
find where they end and simply splice on the plug you need

that red single pin connector is odd
oil switch plug looks odd
the regular right angled temp gauge connector seems missing ..is that the red one ?? is the wire purple .. it usually is

but yeah it's different to be sure ..but you have enough you should be able to work up a really nice front engine harness with a little effort

sure plug N play would have been nice but you can still make this work

I hope you're not paying the dealer to do this .. 'cause it's to simple to be paying for , it's just straight bench time .. with a book on your knee.. so to say

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not paying the dealer, I work at a Mercedes-Benz dealer. I'm the assistant shop foreman so I leave it on a lift and work on it before or after work. it's nice because I have an endless supply of tools and all the shop equipment. and yes those 2 single pin wires are odd as my old harness didn't have them. So I think i will print some wiring diagrams and start pinning out wires out. this wiring is very basic compared to what I normally deal with. at least there is no flexray on Can networks on the vehicle. lol.

Update.... so I drove over to the dealer and compared both the old and the new alternator harness. they are completely different. only about half the wire colors match and it's simply not for this model. unless this is an updated part. So with that said I can try and get my money back or use both and build a new one from scratch... your thoughts.

does anyone have a diagram for the connectors that are under the battery tray. I can't seem to find anything that identifies pin location and where each wire goes. i think it time for me to purchase a service manual.

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Originally Posted by malloy

does anyone have a diagram for the connectors that are under the battery tray. I can't seem to find anything that identifies pin location and where each wire goes. i think it time for me to purchase a service manual.

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If you're going to rebuild the harness, you may as well get the service manuals. They're really nice. I just built a new injector wiring harness for my CSX, and having the supplement for that was invaluable. If you're in a real hurry, just let me know and I can try to scan my 86 diagrams for you.

if you could scan them that would be great. I going to order the 86 factory service manuals and the shelby supplement. I need to get the vehicle running in the next week as it's going to the body shop for a new paint job. thanks in advance

OK. I'll see what I can get up. The files will be large, and my internet is pretty slow. I guess I could upload them here as attachments. I'm sure they'll be legible even with the small file sizes.

Here are a couple pics of stock turbo L-body alt. harness and larger car turbo harness for 1985 (used the larger alternator). You should be able to use the 1986 harness with some minimal changes. You really need some FSM if your going to work on your vehicle. Although much improved over 1984 vehicle electrics was still not great in 85 and 86. Electric gremlins plagued these cars even when new, now 35 years later, it is even more of an issue.
Todd

thank you for the pics. I ordered the servce manuals today. also forgot that we have alldatapro here at work. that provided some info. can you give me the pin locations for the coolant fan and the oil sensors on the front of the motor.. thanks again.

Question.. on the small 2 pin connector are those the 2 wires for the oil sensors? my old harness is so bad I can make out the colors

The harness in Todd's second photo looks like the harness you got from me via Ebay.

Okay,
On the engine side of harness, the oil light sensor (idiot light) used the single spade type connector. It is light gray in color. This is connected to the smaller sensor on oil distribution block. The second larger oil pressure gauge sensor connector used a 90° round style connector. That is also a gray wire with a yellow tracer. That is also on oil distribution block. Both of these connectors feed into a separate 2 pin connector by the battery tray with two spade terminals in a --I style (perpendicular to each other) plastic locking connector.
As far as the fan connector, the light green is +12 volt from the fan relay. It gets plugged into 8 way plastic connector between black with white tracer and black with green tracer. = = = =. The black (ground) terminal coming off the fan connector is spliced into the ground cable inside the alternator harness. Hope this helps some.
Todd

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Originally Posted by 4 l-bodies

Okay,
On the engine side of harness, the oil light sensor (idiot light) used the single spade type connector. It is light gray in color. This is connected to the smaller sensor on oil distribution block. The second larger oil pressure gauge sensor connector used a 90° round style connector. That is also a gray wire with a yellow tracer. That is also on oil distribution block. Both of these connectors feed into a separate 2 pin connector by the battery tray with two spade terminals in a --I style (perpendicular to each other) plastic locking connector.
As far as the fan connector, the light green is +12 volt from the fan relay. It gets plugged into 8 way plastic connector between black with white tracer and black with green tracer. = = = =. The black (ground) terminal coming off the fan connector is spliced into the ground cable inside the alternator harness. Hope this helps some.
Todd

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THANKS!!!! On my new harness the 2 pin connector is actually a 4 pin. it has a solid grey, grey with yellow tracer and a black with an orange tracer. I don't see the need for the black with orange, so I will just put the 2 pin connector housing in place of the 4 pin housing. everything else looks pretty close and I'm nearly done. also on the new harness the blue with a black tracer has 2 wires instead of 1. ???

I also have a solid purple with a 90 degree, that should be for the sensor in the head... correct?

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Originally Posted by malloy

THANKS!!!! On my new harness the 2 pin connector is actually a 4 pin. it has a solid grey, grey with yellow tracer and a black with an orange tracer. I don't see the need for the black with orange, so I will just put the 2 pin connector housing in place of the 4 pin housing. everything else looks pretty close and I'm nearly done. also on the new harness the blue with a black tracer has 2 wires instead of 1. ???

I also have a solid purple with a 90 degree, that should be for the sensor in the head... correct?

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Yes it should be.

So i'm almost done and should know the outcome soon. I have 1 wire that is in question. it's a black with a white tracer and the wire has a black plastic thingy in series with it. ( possible fuse or diode) this were as of now doesn't go to anything and I just dangling there. it's coming off the 6 pin plug under the battery tray

I think that might be for the AC? That stupid connector doesn't show up in the diagrams with all wires coming off of it. They break it down and show only what's in the system on that page. It's frustrating when they do that.Attachment 64197Attachment 64198

yes, these dodge wiring diagrams are a nightmare. I'm so use to mercedes ETM's and how the German's lay everthing out. I looked on all my diagrams and I couldn't find that dam wire. also what's up with then gauge wire with thick --- insulation. must be an 80's things. In the future probably going to convert all the connectors to a more modern style.