The owner of a Volvo FH contacted us because his truck could no longer start after he took a break in a parking lot near 63450 Hanau. As other electrical systems in the vehicle were also giving out several faults, we sent our electrician to Hanau in order to check the wiring.
The main cause of the fault was a short circuit that had damaged several fuses, which in turn had to be replaced. The electrician located the broken fuses, replaced them and the Volvo was able to set off without any further problems.
Truck breakdown - electrical problems
After tyre and engine problems, electrical faults are the third biggest cause of truck breakdowns. Broken or corroded batteries, followed by cracked wiring and damaged switches and relays are the most common. For safety and comfort reasons, modern vehicles are being fitted with more and more complicated electrical systems, which are becoming increasingly difficult to repair. Despite updated diagnostic systems, which are designed to make it easier to find problem areas despite the increasing complexity, in almost all cases only a specialist can help. The good news is that many causes of damage can be rectified directly at the parking lot without having to tow the truck to the workshop.
Truck starting problems - checking the electronics
If a truck will not start, this is often due to faults with it's electrical components, especially if the lights flicker or there is no response at all. A multimeter can be used to check the battery voltage, which should correspond to the manufacturer's specifications. A clicking noise when trying to start is a suspicious sign that the starter motor is faulty. If you can rule out both the starter motor and the batteries as the cause, the alternator may be faulty, which can be recognised by the battery charging slowly or not at all. In these three cases, it is usually not possible to avoid buying and then replacing the faulty part. However, due to the complicated wiring of the truck electronics, all further steps should be left to a qualified professional and under no circumstances should you attempt to carry out repairs yourself.
Truck battery drains by itself
Another complaint is truck batteries that continue to drain despite inactivity. First of all, it should be ruled out that all lights and secondary systems, including the radio, power windows and a variety of possible truck accessories, are not actually switched off while the truck remains inactive. In some cases, it can happen that components draw electricity parasitically even when switched off, which can be due to defective switches or relays. If the battery is not sufficiently charged despite regular use, this is a possible indication of a faulty alternator.