873120 Junction Block | Genuine Volvo Penta Part

🔧 Product Description

Genuine Volvo Penta charge distributor for charging two batteries, listed in the note for alternators from 12 to 28 V up to 60 A, from the Alternator, Charging, Electric Motor, Electric Drives group. It weighs 0.721 kg and covers 171 applications across the TAMD, AD, D, TMD, TD and MS series. The variant record gives a wider 6-50 V and a maximum of 70 A, so check both figures against your charging system. The accessories catalogue describes the charge distributors as specially adapted for Volvo Penta alternators, able to charge two independent battery circuits at once, and says the starter motor battery is always charged even when onboard consumption has been heavy and the second battery is flat; the 12-24 V, 50-60 A distributor is the one it describes as carrying a sensor that monitors the voltage of the battery in use. It replaces 859499 and 858968, catalogued earlier as junction blocks.

🚤 Compatibility

• Engine Family: TAMD, AD, D, TMD, TD, MS, BB, DP, SP, HS, KAMD, MD, KAD
• HP Range: 40-75 HP

Full model list at the end of this description.

⚙️ Key Features

• Charges two independent battery circuits at the same time
• For alternators 12-28V up to 60A in the note; 6-50 V and maximum 70 A in the variant record
• Starter motor battery is always charged, even with a flat second battery
• 0.721 kg
• Replaces 859499 and 858968
• The starter motor battery is always charged, even when the second battery is flat
• Specially adapted for Volvo Penta alternators
• Rating: 6-50 V / max 70 A
• Also supersedes Volvo part number 840638

🔌 Function

Splits the alternator's output between two battery banks, charging both while stopping either from discharging into the other and keeping the starter battery supplied first.

⚠️ Common Signs of Failure

• One battery charging while the other does not
• Both banks going flat despite a healthy alternator
• Unit running hot, or discoloured around the studs
• Terminals corroded or loose on their studs
• Charging behaviour that changes with which bank is switched in

🛠️ Service Notes

• The note gives 12-28 V up to 60 A and the variant record 6-50 V at a maximum of 70 A, so check your alternator output against both
• The 160 A distributor is 3840597 if your alternator output is beyond this one's rating
• Keep the stud connections clean and tight, since a loose stud reads as a failed distributor
• The descriptive text for the charge distributors covers alternators of 12-24 V and 50-60 A, and states that distributor is equipped with a sensor for directly monitoring the voltage of the battery in use
• Check the rating printed against this part number against the charging system it will serve

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 873120 → Supersedes 859499 → Supersedes 858841

OEM / Related Numbers

• 858968 earlier number superseded by this part
• 859499 earlier number superseded by this part
• 858841 earlier number superseded by this part

📦 Condition

• Genuine Volvo Penta part
• Brand new
• Supplied in original or equivalent packaging

🔎 Full Model Compatibility

Typically suits:

• Volvo Penta 740B, 501B, 570A, 572A, 430A, 430B, 431A, 431B, 432A, 434A, 230A, 230B, 250A, 250B, 570, 500B, 430
• Volvo Penta D2-40, D2-40B, D2-40F, D2-55, D2-55B, D2-55C, D2-55D, D2-55E, D2-55F, D2-50F, D2-75, D2-75B, D2-75C, D2-75F, D2-60F
• Volvo Penta TAMD31L, TAMD31L-A, TAMD31M, TAMD31M-A, TAMD31P, TAMD31P-A, TAMD31S, TAMD31D, TAMD31P-B
• Volvo Penta TAMD122A, TAMD122A/C, TAMD122AF, TAMD122D, TAMD122P-A, TAMD122P-B, TAMD122P-C
• Volvo Penta TAMD74P-A, TAMD74P-B, TAMD74A, TAMD74C-A, TAMD74C-B, TAMD74L-A, TAMD74L-B
• Volvo Penta DP-C, DP-C1, DP-D, DP-D1, DP-A, DP-A2
• Volvo Penta TAMD41D, TAMD41H-A, TAMD41H-B, TAMD41P-A, TAMD41P, TAMD41P-B
• Volvo Penta AD31D, AD31D-A, AD31L-A, AD31P-A, AD31XD
• Volvo Penta TAMD162C-C, TAMD162A, TAMD162B, TAMD162C, TAMD162C-B
• Volvo Penta MD2010, MD2010B, MD2010-C, MD2010-D
• Volvo Penta MD2020, MD2020B, MD2020-C, MD2020-D
• Volvo Penta MD2030, MD2030B, MD2030-C, MD2030-D
• Volvo Penta MD2040, MD2040B, MD2040-C, MD2040-D
• Volvo Penta MD22, MD22A, MD22L, MD22P
• Volvo Penta AD41D, AD41L-A, AD41P-A
• Volvo Penta KAD42A, KAD42B, KAD42P-A
• Volvo Penta KAD44P, KAD44P-B, KAD44P-C
• Volvo Penta KAMD42A, KAMD42B, KAMD42P-A
• Volvo Penta KAMD43P, KAMD43P-A, KAMD43P-B
• Volvo Penta KAMD44P-B, KAMD44P-C, KAMD44P-A
• Volvo Penta SP-C, SP-A2, SP-C1
• Volvo Penta TAMD165A, TAMD165C, TAMD165P
• Volvo Penta TAMD72A, TAMD72P-A, TAMD72WJ-A
• Volvo Penta TMD22A, TMD22B, TMD22P-C
• Volvo Penta D41D, D41L-A
• Volvo Penta D45BPP, D45A
• Volvo Penta TAMD102A, TAMD102D
• Volvo Penta TAMD163A-A, TAMD163P-A
• Volvo Penta TAMD42WJ-A, TAMD42B
• Volvo Penta TAMD63L-A, TAMD63P-A
• Volvo Penta TAMD71B, TAMD71A
• Volvo Penta TAMD73P-A, TAMD73WJ-A
• Volvo Penta TMD31D, TMD31L-A
• Volvo Penta TMD41D, TMD41L-A
• Volvo Penta BB231A
• Volvo Penta BB261A
• Volvo Penta HS1A
• Volvo Penta KAD300-A
• Volvo Penta KAD32P
• Volvo Penta KAD43P-A
• Volvo Penta KAMD300-A
• Volvo Penta MS2B-A
• Volvo Penta MS4B
• Volvo Penta MS5B
• Volvo Penta TAMD103A
• Volvo Penta TAMD121D
• Volvo Penta TAMD22P-B
• Volvo Penta TAMD60C
• Volvo Penta TAMD61A
• Volvo Penta TAMD62A
• Volvo Penta TAMD75P-A
• Volvo Penta TD30A
• Volvo Penta TD31ACE
• Volvo Penta TD40A
• Volvo Penta TD45B
• Volvo Penta TMD102A
• Volvo Penta TMD121C
• Volvo Penta TMD122A