* When the trailer is short-circuited / overloaded, the trailer converter automatically interrupts the faulty function. When the short circuit is removed, the function in question works again. This avoids changing the fuse.
* With lamp simulation for activating the trailer’s indicator light (C2) in the cab, in the event of a short circuit or ground falling off, the control lamp (C2) goes out.
* Output voltages on stop-, rear-, fog-, reversing lights must be measured with a true RMS voltmeter..
Always remember to add a minimum of 2W load when testing measurement.
Why lamp simulation for flashlights?
Most flashing relays measure the amount of power that is connected, and indicate on the cab control lights whether the correct number of lamps is available and whether they are the correct power.
This is defined e.g. on the flash relay as 3 + 1. That is, 3x21W on the trailer + 21W on the trailer.
In the cab there are 2 control lights, C1 is for the trailer and C2 is for the trailer.
In many flash relays, the current curve is measured with fairly high precision (see curve diagram).
For example, if an 18W lamp is used instead of a 21W lamp, the C2 lamp will turn off and indicate faults.
In order for indicator light C2 to show correctly when connecting a 12V trailer, a lamp simulation is necessary because a 12V / 21W lamp has a power consumption of 1.85A (Illustrated with the current curve in Fig. 2), whereas a 24V / 21W lamp has a power consumption of 1.0A (Illustrated with the power curve in Fig. 1.).
If the method is used with a series resistor or a linear converter to change the voltage from 24V to 12V instead of using lamp simulation, the disadvantage is that the control relay’s control function will perceive a 12V-21W lamp as a load of approx. 38W instead of the expected 21W, so the indicator light C2 will often show incorrect.
The TLUB is designed to simulate a power curve similar to the power curve of a 24V lamp, giving the correct load of 21W and thus correct display.
TLUC is designed with a simpler form of simulation than TLUB. Here, a combination of resistance and pulse technique is used. This technique causes most flash relays to indicate approximately correctly.