In this roundtable discussion, BUSRide Maintenance spoke with experts in the field of collision repair about electrical componentry – repairing, replacing and common pitfalls.
Please provide a summary of your capabilities in electrical component repair.
Jon Savitz: Our capabilities [at ABC Companies] in electrical component repair consists of diagnostic training which develops troubleshooting skills amongst our technicians to help identify the problematic component. We also have specialty tools that have been developed to determine if a fan clutch is engaging at too high of a voltage requirement. We perform these tests during PMIs (Preventive Maintenance Inspections) to prevent unexpected failures when in service. We generally replace electronic and electrical components if the repair requires more than regular maintenance items such as brushes.
Steve Walther: CoachCrafters provides experienced diagnostic abilities in heavy duty vehicle electrical systems including multiplex zone networks. We are experienced in the installation, programming and diagnosing of various electrical components and systems. Examples include E-Fan cooling systems (EMP and Modine), modern drive train electronics, destination signs, passenger counter and security cameras.
Dale Carson: For over 30 years, Complete Coach Works (CCW) has dedicated its resources toward the retrofit, accident repair, rehab, and remanufacture of buses. Among our services are electrical component repair solutions. We have the resources and technicians to ensure that repairs are performed correctly, quickly and economically. As a full-service provider of all transit needs, we can diagnose any faults on electrical systems including power, starting, charging, engine, gearbox, retarder, road lighting, interlocks, kneeling, doors, ramp, warning lights, buzzers, bells, and interior/exterior lighting.
James McClain: MCI’s electrical repair capabilities encompass all aspects of our support network. Our electrical technical experts are available 24/ to help a driver troubleshoot electrical malfunctions out on the road. Experts in our call center at 800-241-2947 are prepared to talk operators and drivers through any issue on our coaches from ECM modules to camera systems and beyond.
Beyond emergency and troubleshooting issues by phone, we have highly experienced Technical Solutions Managers (TSMs) available in the field throughout the U.S. and Canada. So, if a customer’s maintenance team needs assistance with electric repairs, they call on their TSM or bring the coach directly to an MCI Service Center. Our technicians are factory trained on all electrical systems to bring coaches back to OEM standards, following the engineering electrical schematics of the original model design. MCI also offers fast access to OEM electrical parts through NFI Parts.
Today’s electrical systems are highly sophisticated. MCI takes a collaborative approach in repair, often working with the TSM and NFI Parts representative to make sure only the right part is used on each case to meet OEM standards.
What electrical components require specialized attention after damage, so that equipment can function properly?
Walther: It is critical for all electrical components affected by the damage to be thoroughly inspected. But, it is highly recommended for electrical harnesses to receive specialized attention. Harnesses control many important safety systems and can be fragile. In addition, harness problems can be difficult to diagnose. Buses rely on multiple electronic control modules to operate various systems. In most cases, these modules rely on a singular communication circuit.
Savitz: The types of components include lane departure camera, automatic cruise control system, TPMS, nodes, ECMs, air conditioning compressors, fan clutches, condenser and evaporator fans. Every electrical component should be thoroughly checked by a competent technician following an event that could have damaged the suspect component. If any sign of physical damage is discovered, including the slightest bend, dent, misalignment or crack can cause the life of the component to be compromised. In addition to physical damage, every component should be checked for functionality and performance. Any performance deficiencies should be further investigated to identify the source of the faulty component.
Carson: Typically, electrical component issues are caused by damage to wire harnesses, connectors, and associated electrical components. In this event, our technicians will either replace or repair the harnesses to meet the requirements of the customer. However, understanding issues with an electrical system depends on where the damage to the bus is located. There could be issues with multiplex panels, HVAC system, doors, driver’s area components, rear engine components, charging components, sensors, etc. Our advanced diagnostic and in-house certified technicians can locate shorts, grounds, opens, and resistance problems in the electrical system to effectively determine the cause of malfunction, and complete the necessary repair or replacement.
McClain: The on-board electrical systems are controlled by multiple ECUs (electronic control units) and ECMs (electrical control modules.) If any of these are damaged they must be replaced and programmed in order to properly function. The ECMs always have to be operating properly. These days, a coach has a network of three data-lines on-board with a single harness connecting to all the modules. If a module fails it must be replaced to OEM specifications. All welding procedures also must follow OEM specifications.
If a technician is trained properly –electrical problems can be easily solved. For example, if the interior lights on a coach fail, any MCI-trained technician can make a speedy and correct fix. We consider every aspect of electrical systems when training our representatives and field experts.
In the case of complex electrical systems, when should operators know to replace rather than repair?
Carson: Electrical components on a bus are vital to the vehicle’s operation and are becoming more complex with today’s advanced technology. When a vehicle system is inoperative, or experiences intermittent power caused by damage to an electrical component, our team of experts will replace the damaged component. We can repair the component; however, in our opinion this can cause lingering issues. To avoid these issues altogether, and provide our customers with a better repair, our technicians will replace the damaged component and have the vehicle functioning again quickly.
Savitz: A general rule of thumb is if the labor and parts are expected to cost 50 percent or greater to repair a damaged device, replace it.
Walther: Many times, it is best to replace rather than repair when dealing with electrical systems that have been damaged. This is due to their intricate organization and layout. Casing or housing damage are likely indicators that they allowed the elements to access internal circuits. This can severely damage the interior wiring and cause electrical components to malfunction.
McClain: If a mux (multiplex) module fails it must be replaced and programmed, but if it has a bad output or connection, that can be swapped out. However, any harness damage must be replaced, not patched. You wouldn’t patch a light or a door. In short, connections can be repaired, but actual damage to the control means replacement in every instance.
It’s critically important to get the right electrical part as well. For example, a proper electrical plug is specified by MCI, and it is there for a reason. NFI Parts exists to get you exactly what you need for that problem and that specific coach. In fact, ordering from NFI Parts safeguards your purchase because the NFI Parts representative has to compare the electrical part with the precise coach design specs and drawings before completing the transaction. That saves operators time and money. Additionally, our regional TSMs visit customers frequently to collaborate on electrical repairs offering their expertise and showing a customer’s mechanic how to make the repair correctly.
What considerations should be made for fire or water damage?
McClain: For all fire and water risk, all J boxes containing electrical controls need to be well-sealed and maintained. All electrical connections need to be secure and connectors shouldn’t be missing any seals. It’s also important that all main cables are tight and clean.
Fortunately, all new MCI coaches are now equipped with Amerex fire suppression systems that engage automatically and are designed to suppress fire at an early stage. That helps keeps passengers safer and reduces the chance of major damage and costly repairs to the vehicle.
If a thermal incident occurs that engages the Amerex system, there are specific instructions and fire-rated parts required for the repair. The NFI Parts representative can walk operators through that too, and MCI Service Centers can make the repairs.
Again, prevention is the backbone of maintenance and it always starts with pre-trip inspections made by well-trained drivers. They should be familiar with the Amerex system and make sure it is functioning properly.
For older-model coaches without fire suppression, NFI Parts offers Amerex system kits that can be retrofitted on a number of MCI E, J, and D-Series model with installation available at all MCI Service Centers. Operators can save on insurance and preserve the value of their coach by adding Amerex.
Walther: The presence of fire and water damage, often suggests that corrosion has occurred. Corrosion can make a repair more tedious and increase labor time. It can also result in serious negative effects down the road if not taken care of properly. In addition, when an electrical component has been affected by fire or water, the internal circuits are most likely damaged beyond repair. Last but not least, the mounting location and integrity are very important. All of these factors drastically increase the chance of discovering hidden damage.
Savitz: In the case of fire damage, we replace components if there are signs of smoke and heat damage. For water damage, we replace the component and the electrical pins. If salty water, we will replace the wiring in most instances.
Carson: Some electrical components damaged by fire or water can be repaired depending on the component and amount of damage. However, it is important to consider the repaired components may not function properly in the long run. After water or fire damage, electrical components are more susceptible to corrosion and the issue of reliability may arise. In either case, a complete diagnostic must always be performed to single out the cause of the malfunction.
What pitfalls should technicians avoid when reinstalling electrical components after a collision?
Savitz: Technicians should ensure that the mounting surface is not warped or damaged in any way and that the component sits with an even amount of pressure on the mounting points so that no torsional stress is placed on the component.
Ensure that all insulation and “P” clamps are of original OEM design and that the wires are not chaffing against any other objects.
If you have failed components such as notes or ECMs, you should make sure that you know the root cause of the failure prior to installing a new unit so that the new unit is not damaged.
McClain: Improperly trained technicians can make serious mistakes. MCI suggests specialized systems training as an investment in the business as well as always following proper install procedures, no cutting corners on replacement parts and always double-checking any repair.
The best option, we feel, is bringing a coach directly to an MCI Service Center for electrical repairs after a collision because we have the capability to replace the harness and install modules to bring the entire repaired coach back to factory standard.
MCI coach models are Altoona tested and in every collision repair, we bring the coach back to those standards protecting the value of your coach investment once complete.
Walther: Technicians must thoroughly inspect all electrical and surrounding components to ensure nothing was missed. It is necessary to always take precautions per the vehicle maintenance manual to avoid system overloads or short circuits. Other vehicle components can also be damaged in the process if the manual is not followed. Also, if a technician fails to review and understand safety guidelines, then there could be severe consequences. The technician can gravely injure himself and put his life at risk.
Carson: Diagnosing electrical problems, especially intermittent problems, can involve a fair amount of time. Most electrical issues can be traced to bad grounds such as corrosion or poorly performed repairs. When electrical components are removed for repairs or replacement, technicians must be mindful of which parts need to be reconnected and make sure they are all reattached correctly. A thorough inspection of the electrical system then needs to take place to ensure it is functioning properly before bus delivery.
What factors are driving innovation in the field of repairing extremely damaged buses?
Carson: As previously mentioned, the transit industry is undergoing rapid technological advancements. Newer buses have electrical systems that are unfamiliar to some technicians. Today, training in this field is of the utmost importance for the understanding of complex electrical systems and electrical schematics in order to troubleshoot and repair electrical faults and component failure. Our learning approach involves courses and hands on training that enables our technicians to become ASE certified and experts in their field. Our certified technicians are trained to follow a unique diagnostics approach that will efficiently and effectively find a solution to all electrical issues.
Walther: The largest factor driving innovation is the advancement of computer diagnostics. Buses are becoming more and more heavily computerized. Diagnostic programs and systems are also becoming more sophisticated in order to be compatible with newer vehicles. This type of technology allows for faster, more reliable and precise diagnosing. And, vehicle information and resources are more readily available.
McClain: Operators need to be sure their technicians are well trained for today’s complex electrical systems. We focus on that at MCI Academy and at every MCI Service Center.
At our Service Centers, all of our technicians are trained to a singular standard whether they’re dealing with HVAC or general electrical systems throughout the coach. At MCI Academy, we’ve deepened our electrical course structure to include 101, 201 and 301-level specialization.
We’re investing in training, making sure every MCI Service Center technician completes all three levels of HVAC and electrical training. MCI offer the same training to our customers’ technicians through MCI Academy and its online Learning Management System (LMS) that can be accessed at any hour of the day or night, and it’s free to all MCI customers.
Savitz: The factor driving innovation of extremely damaged buses are mainly unusual parts sourcing, cost and downtime. However, it still comes down to skilled labor and diagnostics. We spend thousands of dollars per year training our technicians on how to properly repair and maintain vehicles. Depending upon the job description some get certified in welding, others in electrical repairs, others in alignment etc. It takes a team of certified and/or trained technicians to properly diagnose and bring severely damaged buses back into service.