W124 outside temperature display black? Replace A1245420005

On the W124, the outside temperature display was optional equipment, and on many cars today it no longer works properly. The typical pattern: first a dark band appears at the bottom edge of the display, then the discoloration creeps upward until the temperature can no longer be read at all. Other units simply stay blank. Before you start looking for sensors and wiring, it pays to narrow the problem down systematically – because in most cases the unit itself is the problem, not its surroundings.

Symptoms

What matters is telling apart whether only the screen of the outside temperature display is affected or the entire instrument lighting.

Symptom	Likely cause
Display turns black from the bottom edge	Aged LC display in the unit
Display completely blank, no digits	Display or electronics of the unit defective, alternatively connector with no contact
Digits readable, but no illumination at night	Illumination of the unit or connector
Displayed temperature is obviously implausible	More likely the sensor or supply wire – not necessarily the unit
Outside temperature display and Instrument cluster lighting dark	Not to be confused with: dimmer or instrument lighting – see Instrument cluster lighting dark? Check the dimmer

Causes

An LC display is not a component built to last forever. In the dashboard it is exposed to strong temperature swings over decades: heat behind the windshield in summer, frost in winter. UV light adds to that. Over time the liquid crystal layer changes and the display goes dark – typically starting from the bottom. It will not get better on its own.

In addition, solder joints and plug contacts age. A loose or oxidized connector can cause the unit to work one moment and not the next. Important to know: not every outside temperature display is the same. The W124 comes in versions with a 6-pin and a 10-pin connector, plus other variants. The unit described here is the 6-pin VDO version.

Testing it yourself

Work from the simplest to the most involved:

1. Look closely at the display. A dark haze growing in from the edge is already the diagnosis: the display has aged. Only a new display or a different unit will help here.
2. Compare the illumination. Switch on the lights and turn the dimmer. If only the outside temperature display stays dark, the fault is in the unit itself. If the instruments are dark as well, look at the dimmer and the lighting first.
3. Check the connector. Remove the unit, check the connector and pins for corrosion and bent contacts, and count the pins. That way you know right away which version is installed.
4. Read off the number. Note the part number printed on the unit. Only with an identical number and pin count is a replacement part sure to fit.
5. Check the plausibility of the readings. If the display reads cleanly but the temperature is obviously wrong, the fault is more likely in the sensor or the wiring – a new unit will not help then.

Solution

If the display is black or blank and the connector is fine, replacing the unit is the direct route. We supply the Genuine Mercedes-Benz outside temperature display A 124 542 00 05 from VDO with a 6-pin connector – with a new display, tested and fully functional. The price is 189,00 €.

If your unit has a different number or a 10-pin connector, repairing your own unit is often the safer route – you can read how that works in the guide Outside temperature display defective or black? How to repair it. You can find more tested parts for the cockpit in the category Speedometers & instrument clusters.

Compatible vehicles

The overview reflects only what's documented for this part.

Model series	Version	Note
W124 (E-Class)	Outside temperature display VDO, 6-pin	fits per parts data
W463 (G-Class)	Outside temperature display VDO, 6-pin	fits per parts data
W124 with 10-pin or other unit	not covered	Limitation: only the 6-pin version A1245420005

No other model series are documented for this unit. What counts is the number and pin count of your removed part. Compatible vehicle categories: W124 and W463 (G-Class).

FAQ

Why does the screen of the outside temperature display in the W124 turn black?

The liquid crystal display ages. After decades of heat, cold and UV light, it typically darkens from the bottom edge until no digits can be read any more. This is an age-related defect of the display itself, not a wiring or operating fault.

What is the part number of the 6-pin outside temperature display for the W124?

The Mercedes part number is A 124 542 00 05 (A1245420005), manufacturer VDO, version with a 6-pin connector. Before buying, compare the number and pin count of your removed unit.

Does the A1245420005 unit also fit the G-Class?

According to the parts data, the A1245420005 unit fits the W124 and the W463. What counts is the number on your removed part: if it matches and your unit also has a 6-pin connector, the fit is confirmed.

Can I have my own outside temperature display repaired instead of replacing it?

Yes. If your unit has a different number or pin count, or you want to keep your own part, the display in your unit can be renewed. We describe the process in the guide to repairing the outside temperature display.

How much does a tested outside temperature display A1245420005 cost?

The unit with a new display costs 189,00 Euro. Every piece is tested before shipping and fully functional; currently 6 pcs are in stock.

KFZTeile-Thot is a specialist business for tested and refurbished Mercedes parts with its own test benches. Displays, relays and instrument clusters are tested here before shipping – over 1,000 positive eBay reviews reflect that. Not sure whether this unit fits your car? Call us at +49 179 8991069 (Mon–Fri 8 am–6 pm) or write via our contact form – the fastest way is with the VIN and the number of your removed unit.