[ Physical faults · 5 min read ]
Burnt or melted white connector on the Elektroblock
The white jacks of the Elektroblock's Block 2 go black and, over time, end up melting. It's not a plastic quality issue — it's sustained overcurrent through a loose contact. This guide shows you how to diagnose and repair it.
Why it happens
The Block 2 connector on the Elektroblock is a 6-way white JPT connector that carries high-current signals: starter battery positive, D+ from the alternator, and auxiliary battery supply. Each pin is designed to carry up to 20 A in continuous service.
When a contact becomes slightly loose over the years —thermal cycling, vibration, slight corrosion— the resistance between the male pin and the female contact rises. Even a few milliohms are enough: at 20 A, that’s several watts of heat on the pin, continuously. The plastic housing melts around that pin first, then spreads.
How to recognise it
Visual signs on the connector:
- Light yellowing of the white plastic near one or two pins. Early stage; still repairable without consequence.
- Dark brown or black staining on the plastic around pins. Advanced stage; the pin is already overheating in service.
- Deformed plastic, flow marks or the pin visibly tilted. Terminal stage; often the pin on the EBL board side is also damaged.
Smell test: a persistent “hot plastic” smell inside the service panel is a reliable indicator even before visible marks appear.
Diagnosis before dismantling
With the EBL powered and the auxiliary battery charging, touch the back of the Block 2 connector carefully. If it’s noticeably hot (over about 50 °C) at any pin, that pin has a bad contact. A thermal camera makes this trivial but a finger test works.
Repair procedure
- Disconnect the EBL from mains and the batteries. Discharge the capacitors.
- Remove the melted connector housing. The pins may come out individually.
- Clean the female contacts on the EBL side with contact cleaner and a small brush. If any pin is already blackened or oxidised, it needs to be replaced on the board.
- Fit a new JPT 6-way connector with new crimped contacts on the vehicle side.
- Bench test under load for 2-3 hours to confirm the new contact runs cool.
Workshop cost: €90-€120 including the new connector, bench test and warranty.
How to prevent recurrence
- Every 2-3 years, disconnect and re-seat the Block 2 connector during routine motorhome maintenance.
- Apply a thin layer of dielectric contact grease on the female side.
- If the EBL has run with a slightly degraded battery (sulphated, under-sized), it has been working harder than designed. Replace the battery first and the problem may stop.
Related guides
- Auxiliary battery not charging — if the melted connector has already cut charging.
- 70 A coupling relay — often the same symptom chain.
- Alternator D+ signal missing — if the burnt pin was the D+ one.
Read next
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Internal components
70 A coupling relay burnt inside the Elektroblock
The 70 A relay that connects the starter battery with the auxiliary one during driving charging is the component that fails most often in Schaudt Elektroblock units. It buzzes, sticks or stays open: three symptoms, one culprit. Here's when to replace it and how much it costs.
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Signal diagnosis
Alternator D+ signal not reaching the Elektroblock
Your motorhome charges perfectly on 230 V mains but when driving on the road the auxiliary battery doesn't go up. The problem is almost always the alternator D+ signal not reaching the Elektroblock. Here's the 10-minute diagnosis.
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Next step
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