Our Ferrari Fusebox Rebuilds: FAQ and Technical Overview

Last updated November 10, 2020

G.T. Car Parts INC provides re-manufactured, upgraded fuseboxes (also known as a fuse board or relay assembly) for many Ferrari models, sold on exchange basis.

We replace the factory adhesive-laminated multi-layer circuit boards with a new single board that has a greater amperage capacity and is more durable than the original. We reuse the original plastic fuse box housing, which is why we sell these as re-manufactured rather than new items. If your housing is damaged, in most cases we can provide a good used one from our stock at additional cost.

All our re-manufactured fuse boxes use rigid modern PCBs with updated materials and revised designs. These boards are manufactured exclusively for G.T. Car Parts and address common failure points while maintaining original appearance and connection style. Our design eliminates common problems of burned out connectors/traces/solder joints caused by original design flaws, vibration fatigue, peeling board layers, and/or corrosion between layers.

Installation is exactly the same as the factory unit. Our fuseboxes do not require any modifications to factory wiring or connectors and preserve the vehicle’s original appearance. We do suggest that when installing a new fusebox you should evaluate the condition of your electrical system, wiring harnesses and connectors. Cleaning and replacement of wiring harness components as needed will ensure best performance from your new fusebox.

Applicable Ferrari models

We can supply remanufactured fuse boxes/boards for the following Ferrari models (including US, Euro and all other market versions of each)At this time we do not supply rebuilt fuseboxes for the following models*
Testarossa
328 GTB/GTS/Turbo
Mondial (all variants)
550 Maranello/Barchetta
– 512TR (coming Q4 2020)
– F512M (coming Q4 2020)
– 400/400i/412
– 456
– F40
– 288 GTO
* If you are looking for a fusebox for any of these models, please contact us as we may be able to provide a new or used replacement unit from our stock.

FAQ: How does the rebuild process work?

We sell these fuseboxes on an exchange basis, your existing fusebox assembly must be shipped to us first.

To complete the rebuild at the base price, we require a good core unit including plastic housing and internal factory circuit boards with intact soldered-on contacts. As the plastic housing is reused, it needs to be undamaged. If you’re wondering whether your fusebox is rebuildable, we can usually evaluate this beforehand if you email high quality photos of the interior and exterior of the fusebox assembly.

Where possible we reuse the original plastic housing as well as any soldered-on contacts that have not been compromised by wear, heat or corrosion. If your housing is damaged, we can most likely provide one from our stock at additional cost.

Our usual turnaround time is 7-10 business days from receiving your original board to shipping out the rebuilt unit. This may vary depending on our workload and component stock. Please contact us via email or phone for current lead times and pricing.

FAQ: How do I order?

First, please contact us directly so we can provide pricing, availability and lead time for the specific model of board you need.

Once we have confirmed your order, we will ask you to ship your original board to our location in Phoenix, Arizona, USA. The relays, fuses, and external wiring harness connectors are not required and we prefer you remove them before shipping the board to us. Once we receive the board, we will send you an email notification that it has arrived and is in the rebuild queue.

When the rebuild is complete, we will contact you to process payment and ship the board back via your choice of shipping services.

FAQ: My original fusebox is very damaged or missing. Can you help me?

Yes, in many cases we can provide a core from our extensive used parts inventory and rebuild this for an additional charge. Because good rebuildable fuseboxes are becoming rarer, we cannot guarantee availability. Please contact us via email or phone for current availability and pricing.

FAQ: Will you sell me the parts so I can rebuild it myself?

We do not sell an unsoldered fusebox PCB or DIY kit. As we do provide a guarantee on these boards (see “Our Guarantee” below), it is necessary for us to disassemble, solder and reassemble and inspect the entire board assembly in house. This way we can be sure that our customers are provided with a product that meets our standards. Additionally, if we need to provide technical support we can do so without uncertainty about the assembly process.

FAQ: What is the difference between the original Ferrari fuseboxes and GT Car Parts’ remanufactured fuseboxes?

The original Ferrari fusebox circuit boards are built out of several flexible printed circuit boards (PCBs) laminated together. The individual electrical terminals (contacts) pass through these boards and are soldered in place. This assembly is vulnerable to failure of solder joints due to the boards’ fragile structure as well as corrosion damage from moisture entering between PCB layers. This process is accelerated by vibration from driving and aging of the board material. High amperage circuits on the board are especially susceptible to heat damage and electrical shorts when the original solder joints have weakened over time.

Our rebuilt fuse boxes use a single, multi-layered printed circuit board (PCB). This new PCB is constructed of durable, rigid, modern materials and directly replaces all functionality of the factory laminated PCB assembly. As all the electrical circuits are contained within the internal layers of a single rigid board, there are no “loose-leaf” circuit board layers, new wiring or other additional components that are susceptible to corrosion/shorting from trapped moisture or long-term degradation from vibration.

Our board is also upgraded with higher capacity 2oz copper traces for high-amperage circuits such as fuel pumps and fans. Modern manufacturing processes allow our boards to have 8 internal layers within the same overall thickness as the original 5 loose-leaf layers. This gives us the ability to design boards with wider traces and route high current circuits through separate layers with less “crowding” from other circuits. This reduces heat build-up in the board and relays, which is one of the major contributors to failure of the factory boards.

All the solder joints on our rebuilt boards have plated through-holes, meaning the solder joint extends through the entire thickness of the circuit board. This greatly improves rigidity and durability compared to the original boards where terminals are only soldered to one layer.

Because the factory plastic housing and electrical contact style is unchanged, our remanufactured fuseboxes are a direct plug-in replacement for the original units and require no additional modifications to your car. When installed, they are visually identical to the factory unit.

FAQ: I have a Mondial 8/QV/3.2/t, is your product compatible with my specific model?

Yes, we can provide rebuilt boards for all Mondials, with minor caveats for certain early models.

Some early Mondial and 400 fuseboxes use cylindrical ceramic fuses instead of modern blade-type fuses. In order to rebuild these fuseboxes, we convert them to use blade-type fuses. This incurs an additional charge, which covers replacing the plastic fuse blocks and fuse connectors. If you have one of these early-style fuseboxes, please contact us for updated pricing and lead times.

Also, use of our fuseboxes in the Mondial 8 U.S. version requires a minor wiring modification. This modification was developed by the Ferrari factory when they discontinued the first version of the factory fuse boards as a spare part and superceded it with the design used on later Mondials. As our boards follow the later Ferrari design, this modification is required for our boards as well. The process is detailed in Ferrari Service Bulletin 80-26, which we can provide on request. If your original board was previously replaced with a newer Ferrari factory board, this modification may have already been performed per the factory service bulletin.

FAQ: I need plastic connectors, crimp terminals, fans, fuel pumps or other replacement electrical components. Can you provide these?

In most cases, the answer is yes. In addition to our line of fuseboxes, we are a full-line supplier of vintage Ferrari parts with an extensive inventory of new and used items. We stock most common failure items for these cars as well as kits for major services and repairs.

We also can provide reproduction plastic connectors (with matching crimp terminals) to replace the white plastic ones that are often burned or melted when original fuseboxes fail. Many of these connectors are no longer available from Ferrari factory sources.

Due to our extensive and ever-changing inventory, we do not list most of the items we stock on our website. Please contact us via email or phone directly for price and availability information.

Technical guidelines for fusebox replacement

  • Our circuit boards are designed to work with the factory wiring configuration of the car, with all original components of the system present and in good working order. Prior to installing a rebuilt fusebox, we suggest performing a thorough evaluation of the electrical system and replacing any damaged or degraded components to bring it back to factory specification. A new circuit board may be destroyed instantly by cars with electrical modifications or malfunctions. While we provide a guarantee on these boards (see “Our Guarantee” below), this only applies to installations in unmodified vehicles in good working order.
  • Many issues that appear directly after installing a remanufactured fusebox are due to incorrect relay layout carried over from the previous fuse board. Due to prior modification or repair, or rolling updates applied by the factory, you may need to adjust your relay layout for proper functioning. The best reference for this is factory wiring diagrams. As our boards are based on later factory revisions of fuse boxes, we generally refer to the later editions of the diagrams for this purpose. We advise checking the wiring diagram itself rather than the relay layout graphic in the owner’s/workshop manual or on printed decals, as these may have outdated information. In particular, several editions of the Testarossa workshop manual have misprints that indicate an incorrect relay in the relay graphic but show the correct one in the wiring diagram itself. If you do not have access to these diagrams or need other technical support, please contact us directly for assistance.
  • We have found that most major electrical problems in the factory boards are caused by fan motor and fuel pump circuits. As the electric motors in these units get older, they gradually become less efficient and draw more amps. The current may be high enough to cause damage even if the fuse does not blow. Replacing the fuse board will not stop this problem, only make it less noticeable by reducing heat build-up in the fuse box area. Damage may still occur at other places on the wiring harness and your overall current draw will still be higher than recommended. We strongly recommend checking ALL fan motors and fuel pumps for worn bearings, seized mechanisms, poor electrical connections and/or excessive current draw, replacing them as needed. We usually have replacement fan motors and fuel pumps in stock.
  • When replacing the fusebox you should check and repair any damage to the wiring harnesses connected to it. If the fuse box has failed, it is possible that there is heat and/or corrosion damage to the plastic connectors, metal crimp-on terminals, and the wiring itself. We can supply new and used wiring harness components, including both the white plastic connectors and crimp-on metal terminals.
  • We have recently found a product to improve the electrical reliability of removable connectors used on many vehicles, including Ferraris. The product, Stabilant, forms a thin film on an electrical contact that becomes conductive when connected. Stabilant is used by many of the high end German auto manufacturers on their electrical terminals. You can order this directly from the manufacturer.
  • We also recommend using a good dielectric grease at all the connections to keep corrosion and its related effects to a minimum. This is especially important on Mondials, considering the location of the fusebox.

Our Guarantee

We are happy to repair or replace at no additional charge any rebuilt fusebox that has failed due to a defect in materials or worksmanship, within 10 years from date of purchase.

Please keep in mind that our guarantee applies only to remanufactured fuseboxes installed in unmodified vehicles in good working order. We reserve the right to deny warranty replacement for a fusebox that has been damaged by improper installation, aftermarket modifications, or an electrical fault elsewhere in the vehicle.