This is my write up for the OM612 engine harness replacement: Part No. A9015402107.
This project is not for the faint of heart. Master mechanics time it at (supposedly) 4 hours. But they have experience of having done it before, the tools and the space that facilitates the removal and replacement. Other DIYyers claim that they can do it in 6 or 7 hours. It took me closer to 24 hours.
Many of the cable ties and electrical connectors are in locations that are hard to get to, several are obscured and several have to be removed and reconnected blind and with little working room. In short, if you can find a shop to do this job at a labor time of 4 hours – run, do not walk – to deliver your van to them and pay them to do the work. If done correctly, you will not regret it. Unfortunately for me, Dr. A pushed me off to Freightliner. When I called and talked to my local Annapolis Freightliner, they said that they would get back with me. They never did. That speaks volumes.
Even though I asked Sprinter-Source members for years to provide guidance from their experiences on replacing an OM612 harness, no one did. The closest help I found was from a posting by JP Cables of Freightliner’s instructions to remove the OM612 manifold – which requires the complete removal of the engine harness but preserving it for re-installation. While it was great guidance, I could not tell what steps where necessary just for the harness removal and replacement v. the manifold replacement.
I have now performed this job. Below I have extensively edited the Freightliner instructions to remove what I think are the steps related only to the manifold removal and replacement, additions for steps that seem to be missed, additional pictures and other guidance. Some steps seem needlessly out of order, but I did not do much to re-order Freightliner’s steps. Reader beware – I may be wrong and I do not represent this as correct.
View attachment OM612 Harness Replacement Guidance HKP.pdf
[HKP> added note] the S-hose from under the manifold to the auxiliary circulating pump located on the firewall is A9018325123. That part does not appear to be readily available in the US except for Europarts SD. The aftermarket part is found for 5124867AA. But that part is for the OM647. The part will kink closed if used as delivered. It will work after a fashion is you cut about 2.5 inches off the pump side of the hose, and wiggle to let the hose settle in the least-kinked position.
[HKP> added note 2] The OM612 harness is no longer available - at least in the US. It is still listed on some UK and RU sites. If anyone orders and receives a harness from those sources - PLEASE REPORT this info to Sprinter-Source.
This project is not for the faint of heart. Master mechanics time it at (supposedly) 4 hours. But they have experience of having done it before, the tools and the space that facilitates the removal and replacement. Other DIYyers claim that they can do it in 6 or 7 hours. It took me closer to 24 hours.
Many of the cable ties and electrical connectors are in locations that are hard to get to, several are obscured and several have to be removed and reconnected blind and with little working room. In short, if you can find a shop to do this job at a labor time of 4 hours – run, do not walk – to deliver your van to them and pay them to do the work. If done correctly, you will not regret it. Unfortunately for me, Dr. A pushed me off to Freightliner. When I called and talked to my local Annapolis Freightliner, they said that they would get back with me. They never did. That speaks volumes.
Even though I asked Sprinter-Source members for years to provide guidance from their experiences on replacing an OM612 harness, no one did. The closest help I found was from a posting by JP Cables of Freightliner’s instructions to remove the OM612 manifold – which requires the complete removal of the engine harness but preserving it for re-installation. While it was great guidance, I could not tell what steps where necessary just for the harness removal and replacement v. the manifold replacement.
I have now performed this job. Below I have extensively edited the Freightliner instructions to remove what I think are the steps related only to the manifold removal and replacement, additions for steps that seem to be missed, additional pictures and other guidance. Some steps seem needlessly out of order, but I did not do much to re-order Freightliner’s steps. Reader beware – I may be wrong and I do not represent this as correct.
View attachment OM612 Harness Replacement Guidance HKP.pdf
[HKP> added note] the S-hose from under the manifold to the auxiliary circulating pump located on the firewall is A9018325123. That part does not appear to be readily available in the US except for Europarts SD. The aftermarket part is found for 5124867AA. But that part is for the OM647. The part will kink closed if used as delivered. It will work after a fashion is you cut about 2.5 inches off the pump side of the hose, and wiggle to let the hose settle in the least-kinked position.
[HKP> added note 2] The OM612 harness is no longer available - at least in the US. It is still listed on some UK and RU sites. If anyone orders and receives a harness from those sources - PLEASE REPORT this info to Sprinter-Source.
Last edited: