mcorm Posted August 30, 2023 Share Posted August 30, 2023 I have a 2000 mack rd688s 8ll the fuse pannel and vecu plugs all went bad so I got a harness from another truck but it was automatic. I need the wiring diagrams for both the auto and manual trucks so I can have them to help me overlay the parts I need to take off the old harness. I tried looking all over Google but haven't had any luck. Thanknyou for your help Quote Link to comment https://www.bigmacktrucks.com/topic/73241-2000-mack-rd688s-cab-wiring-harness-schematic/ Share on other sites More sharing options...
Joey Mack Posted August 30, 2023 Share Posted August 30, 2023 lay both harness' next to each other and trace each wire to see what is different.. chances are that there are wires in auto tranny plugs that are not in the manual plugs. If you have a good set of terminal release tools you can unlock the pins and re-create the plugs to match the original.. are you familiar with how to read the wire codes on those white wires? to me, its actually a very smart set-up that Mack did.. also, I suggest getting a V-Mac III boo. I saw one on E-Bay last week for $55.00 Quote Link to comment https://www.bigmacktrucks.com/topic/73241-2000-mack-rd688s-cab-wiring-harness-schematic/#findComment-537961 Share on other sites More sharing options...
mcorm Posted September 6, 2023 Author Share Posted September 6, 2023 Thank you, I found the only circuit that I belive is different I'd the throttle and the clutch press to start. I'm not familiar with how to read the wiring this is my first mack. Do you believe that vmac3 book will have info on reading the wiring and possible the diagrams I'm looking for? I greatly appreciate the response. I called the dealer and he told me he was going to get a paper copy of what he could get to me by the end of the week. Quote Link to comment https://www.bigmacktrucks.com/topic/73241-2000-mack-rd688s-cab-wiring-harness-schematic/#findComment-538380 Share on other sites More sharing options...
Joey Mack Posted September 6, 2023 Share Posted September 6, 2023 It will.. here is a quick lesson.. On the white wires, which is 99 %of them Is alpha numeric codes.. exp. VJ1-12-.5.. that means... VECU J1 plug, pin 12, wire size .5... Exp #2: EJ2 - 10- .5... Same idea... EECU, J2 plug, pin 10, wire size .5. Does what I wrote make sense to you? This code can be used to check the wire with a DVOM from one end to the other. The book I posted is excellent and has many specs and flow charts for diagnostics.. Jojo Quote Link to comment https://www.bigmacktrucks.com/topic/73241-2000-mack-rd688s-cab-wiring-harness-schematic/#findComment-538382 Share on other sites More sharing options...
mcorm Posted September 6, 2023 Author Share Posted September 6, 2023 Yes thank you. I'm going to try to grt my hands on a copy of that book asap. Much appreciated. Quote Link to comment https://www.bigmacktrucks.com/topic/73241-2000-mack-rd688s-cab-wiring-harness-schematic/#findComment-538385 Share on other sites More sharing options...
Joey Mack Posted September 6, 2023 Share Posted September 6, 2023 Your welcome.. I can be hard for me to post info without either over doing it, or leaving some info out. :). Quote Link to comment https://www.bigmacktrucks.com/topic/73241-2000-mack-rd688s-cab-wiring-harness-schematic/#findComment-538386 Share on other sites More sharing options...
mcorm Posted September 6, 2023 Author Share Posted September 6, 2023 https://drive.google.com/file/d/18q2NFDXvUJ6E8mt69wHVnWZfpaUKNV9O/view?usp=drivesdk Found it Quote Link to comment https://www.bigmacktrucks.com/topic/73241-2000-mack-rd688s-cab-wiring-harness-schematic/#findComment-538391 Share on other sites More sharing options...
Joey Mack Posted September 6, 2023 Share Posted September 6, 2023 thats great... was it a free PDF.? Quote Link to comment https://www.bigmacktrucks.com/topic/73241-2000-mack-rd688s-cab-wiring-harness-schematic/#findComment-538392 Share on other sites More sharing options...
mcorm Posted September 7, 2023 Author Share Posted September 7, 2023 Yes. Thanks for the help. This should answer almost all my questions Quote Link to comment https://www.bigmacktrucks.com/topic/73241-2000-mack-rd688s-cab-wiring-harness-schematic/#findComment-538408 Share on other sites More sharing options...
Joey Mack Posted September 7, 2023 Share Posted September 7, 2023 I have over 20 engine book downloads. I put them on CD's and have a CD folder. I make 2 copies plus the the one that is save on my shop computer.. Quote Link to comment https://www.bigmacktrucks.com/topic/73241-2000-mack-rd688s-cab-wiring-harness-schematic/#findComment-538412 Share on other sites More sharing options...
mcorm Posted September 7, 2023 Author Share Posted September 7, 2023 So I'm just trying to make sure I'm reading this correctly I have a set of wires for the clutch engauge circuit. The wire coming from the vecu is labeled (L7391271 VJ1-9A-0.8) reference to the pinout in the book confirms j1 pin 9 is clutch engage. The other wire coming from it is labeled (L7391253 17-A-0.8 F) Is there a way see what that one is labeled? Quote Link to comment https://www.bigmacktrucks.com/topic/73241-2000-mack-rd688s-cab-wiring-harness-schematic/#findComment-538417 Share on other sites More sharing options...
Joey Mack Posted September 7, 2023 Share Posted September 7, 2023 Did you expose a good bit of the wire to read all the codes? I'm not able to answer that question. Quote Link to comment https://www.bigmacktrucks.com/topic/73241-2000-mack-rd688s-cab-wiring-harness-schematic/#findComment-538421 Share on other sites More sharing options...
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