- Is there a Difference in Quality between Light Manufacturers?

Bosch and Hella appear to be the OE supplier to Mercedes-Benz for headlight units.

Some have asked if there is a difference in quality between, say the Bosch headlights and some of the more economical brands, like DEPO or TYCO. To tell the truth, I don't know for sure. Many who have purchased the DEPO brand (at probably 65% the cost of the Bosch or Hella units) have said that they are perfectly satisfied with the DEPOs. I can comment only on my experience and should mention that I have never seen actual DEPO headlights.

But I have seen the DEPO turn signals. I purchased a set of clear DEPO front turn/side marker signals and installed them. Visually they looked fine. But they didn't engage the attachment fittings in the car properly and also the bulb holder socket did not grasp the bulb holder properly. As a result, one of the lights, fell out of the car somewhere along the interstate, never to be found.

I then purchased a set of Bosch clear signals. When I received the Bosch blinkers, I noticed that one is made in Czech Republic (as both my Bosch euro headlights are), the other in Germany. They both seem to fit well and tight. They "snap" into place when installed (like originals), ie, you hear the latch engaging into the body. The DEPOs wouldn't do that.

My experience may be atypical of DEPO quality.

I took some pictures of the Bosch and the remaining DEPO for comparison. You can see for yourself...

Clear Blinkers Photo 1
Bosch on the Left, DEPO on the Right. Exterior looks seem to show little difference. But notice how the Bosch latch is better formed.

 

Clear Blinker Photo 2
Bosch on the Left, DEPO on the Right
Close up of the latch. The DEPO tangs are mishappened - classic sign of a "short shot" in the injection process.

 

Clear Blinkers Photo 3
Bosch on the Left, DEPO on the Right
Another closeup of the latches. Those plastic tangs are what hold (or don't hold) the lamp assy in the car. The metal spring clips seemed better formed also.

 

Clear Blinkers Photo 4
Bosch on the Left, DEPO on the Right
Bosch has thicker, better formed rubber trim.

 

Clear Blinkers Photo 5
Bosch on the Left, DEPO on the Right
This is where the bulb holder is inserted. Notice how much better formed the 3 key notches and edges are formed on the Bosch. In the DEPO, the bulb holder would spin 360 °, while the Bosch just does a quarter turn and locks.