Heated Rear Window

Beat poor visibility by restoring power to your rear screen’s heated element.

Repairing faulty heated rear window elements.

Heated rear screen repairs are possible, but what’s achievable is limited according to how the element is fitted. If it’s embedded between the inner and outer layers of glass, only terminal and possibly busbar repairs are viable. If the element is stuck to the surface, as on our early MGB test screen, small gaps in the element wires can be repaired using silver electrical conductor paint (£15-£20). It’s easy to use and is worth a go if a new screen is your only alternative. It is not suitable for painting direct to glass, however, just the adhesive layer of the element. This repair demonstrates the replacement of a corroded or missing terminal. In issue 188, I did a terminal repair with the glass in situ, coincidentally on a later MGB rear screen with embedded elements. The procedure is the same.

Don’t fret that 40-Watt soldering iron heat might crack the glass. Work in a warm ambient temperature to avoid extremes of temperature, or warm the screen terminal area with a hairdryer first, if you must.

Key to a successful terminal repair is tinning the contact areas using soldering wire. By doing this, the heat and time required are drastically reduced, minimising risk of damage to the busbar and glass. Once the solder on the terminal and the busbar melts, the soldering tip should be removed without moving the terminal.

Your choice of soldering iron tip is also critical. Use a flat, not pointed, tip to apply quick heat across the terminal surface area.

The heated element was connected to a 12v battery with a 2W dash light bulb running between the screen and the battery + terminal post. It lights up because the circuit is complete, meaning the terminal repair was successful.