Our Ferrari Fuse Boards: FAQ and Technical Overview

Last updated August 6, 2025

G.T. Car Parts INC provides upgraded fuse boards (also known as a fuse box or relay assembly) for a selection of 1979-2002 Ferrari models. We replace the factory laminated multi-piece circuit boards with a new single multi-layer board that has a greater amperage capacity and is more durable than the original. Our board is designed to fit into your original plastic housing and work with the car’s original electrical system.

We offer two options to purchase our upgraded board:

• Board replacement kit: We supply a circuit board ready to install in your existing plastic housing. The circuit board is soldered and inspected by GT Car Parts. You will be required to install the board into the housing, a simple procedure requiring a Phillips screwdriver. This option uses new low profile fuse holders that have a different appearance than the original units.
• Rebuild service: You ship your original board assembly to us and we install the new circuit board in your existing housing. Your original fuse holders are reused so the board has a 100% factory appearance when installed. Turnaround time varies based on our workload but is usually less than 10 business days.

All our re-manufactured fuse boards use durable modern printed circuit boards (PCBs) with updated materials and revised designs. These PCBs are manufactured exclusively for G.T. Car Parts and address common failure points while maintaining original 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.

Our fuse boards do not require any modifications to factory wiring or connectors. They use the same electrical schematic and relay layout as original Ferrari boards. We strongly suggest that when installing a new fuse board you should inspect the condition of the car’s electrical system, including electric fans/pumps, wiring harnesses and connectors. Repair and/or replacement of any damaged or worn electrical system components will ensure best performance and longevity.

WARNING: Electrical systems are dangerous and improper installation can result in damage, vehicle malfunctions and, in extreme cases, personal injury. Installation by a qualified professional Ferrari technician is recommended.

Please review the additional information below and contact us with any questions or for a quote.

Applicable Ferrari models

FAQ: What is the difference between kit and rebuild options?

Board replacement kit: With this option, we send you our new circuit board, ready to retrofit into your existing fuse board housing. No soldering is required. You will receive a fuse board PCB as pictured to the right, along with an instruction sheet and a package of plastic insulating washers. Once the fuse board is removed from the car, you will need to remove relays and fuses, then unscrew first the back cover then the original PCB from the plastic housing. The new circuit board will then drop in and be secured using the new insulating washers and your original screws.

The circuit board supplied with the replacement kit option uses low profile fuse holders that have a different visual appearance than the original large plastic fuse holder blocks on the factory board (see comparison photo below). They function exactly the same as the originals and are rated to 30 amps. We use these because the original fuse holders and matching terminals are no longer available and must be sourced from a dwindling stock of used items. Using these new holders allows us to continue to stock boards for immediate shipment at reasonable cost.

Rebuild service: With our rebuild service, you ship us your fuse board (without fuses and relays) and we install our new circuit board in your original housing, reusing the original fuse holders for a 100% factory original appearance. You will receive an assembled fuse board, all you need to do is plug in relays/fuses and install it in your car. If you would like new relays and fuses, we can also provide a preinstalled relay/fuse kit for an even easier install process.

FAQ: How does the rebuild process work?

First, please contact us directly so we can provide pricing, availability and lead time for the specific model of board you need. We will then ask you to ship your original board assembly to our location. Please include a business card or note with your contact details inside the package. Remove all relays and fuses from the board before shipping. Once we receive the board, we will send you an email notification that it has arrived and is in the rebuild queue.

To complete the rebuild at the base price, we require you ship us a good core unit including plastic housing and internal factory circuit boards with intact soldered-on contacts. We reuse the original plastic housing, the plastic fuse holders and the fuse terminals (condition permitting). If any of these components are damaged, we can usually provide one from our stock at additional cost. If you’re wondering whether your fuse board is rebuildable, we can usually evaluate this beforehand if you email high quality photos of the interior and exterior of the fuse board assembly.

Our usual turnaround time is around 5 business days from receiving your original board to shipping out the rebuilt unit. This may vary depending on our workload and component stock. When the rebuild is complete, we will contact you to process payment and select the return shipping service.

FAQ: My original fuse board 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 usable OEM parts are becoming rarer, we cannot guarantee availability. Please contact us via email or phone for current availability and pricing.

FAQ: What is the difference between the original Ferrari fuse boards and GT Car Parts’ fuse boards?

The original Ferrari fuse boards are built-up 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, or due to electrical faults caused by aging components elsewhere in the vehicle.

Our rebuilt fuse boards use a single, multi-layered printed circuit board (PCB). This new PCB is constructed of durable, rigid, high temp FR4 material 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.

We design fuse board PCBs with higher capacity 2oz copper traces throughout. This means there is additional cross-sectional area for each trace, similar to using a thicker wire gauge in a harness. This helps prevent temperature increases on high-amperage circuits such as fuel pumps and fans. Modern manufacturing processes enable production of PCBs with 8 internal layers in the same overall thickness as the original 5 layer board. This gives us the ability to design boards with more trace area by routing high current traces through separate layers with less “crowding” from other traces. This reduces heat build-up in the board, connectors 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 mechanical and electrical connection extends through the entire thickness of the circuit board. This greatly improves rigidity and durability compared to the original boards where contacts are only soldered to one layer.

The printed circuit boards used in our rebuilds and kits are manufactured in a state-of-the-art PCB manufacturing facility to IPC 6012 Class 3 specifications. Each individual bare board undergoes automated testing using a flying probe system. We then assemble and solder each board in-house, with visual inspections at each step before the finished product is delivered to the customer.

Because the factory electrical schematic, plastic housing and connection style is unchanged, our fuse boards are a direct plug-in replacement for the original units and require no additional modifications to your car. If you choose to have us rebuild the board, it will be visually identical to the factory unit when installed. Boards supplied with the kit for DIY installation have different fuse holders, so they have a slightly different appearance but function exactly the same.

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 fuse boards use cylindrical ceramic “torpedo” fuses instead of modern blade-type ATO fuses. Replacement boards for these models will be fitted with ATO fuse holders.

Use of our fuse boards in the Mondial 8 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 Mondial models. As our boards follow the later Ferrari design, this modification is required for our boards as well. The process is detailed in Ferrari Service Bulletins 80-26 (US cars) and 80-31 (Euro cars), 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 fuse boards, 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 stock OEM quality (Bosch or equivalent) relay kits for each model of fuse board and can pre-install these on your board on request.

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 fuse boards 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.

FAQ: My car is modified, engine-swapped, or has aftermarket accessories installed. Will your fusebox work?

We design our rebuilt fuse boards to work reliably with the original, factory electrical systems in Ferrari vehicles. Due to the extremely large variety of possible modifications, it’s not possible for us to engineer a product that is designed to accommodate aftermarket changes to the electrical system. While we will sell our product to customers with modified vehicles, please understand that our ability to provide technical support for these applications is very limited. We reserve the right to deny warranty replacement for fuse boards used in modified vehicles (see the warranty for more details).

Modifications to the fuse board itself may also void warranty coverage, including remote mounting of fuses/relays, soldered jumper wires or “piggybacked” circuits. Many of these modifications are intended to improve reliability or current capacity. Our product is designed to solve these issues without any additional modifications.

Installation Guidelines

Please carefully review the items below for important details about installing a GT Car Parts fuse board in your Ferrari.

• 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 fuse board, 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 warranty (see “Limited Warranty” section below), this only applies to installations in unmodified vehicles in good working order.
• A very high percentage of support requests we receive are due to the use of failed or incorrect relays. Therefore, as a first step we strongly suggest checking the type and placement of all relays in your fuse board. It’s also a good idea to test all relays for function, especially if you’re reusing the original Bosch “metal top” relays. 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 workshop manuals and/or wiring diagrams. As our boards are based on later factory revisions of fuse boards, 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 can also provide pre-installed new relay sets along with your rebuilt fuse board, contact us for pricing.
• As some original relays are now discontinued, you may need to replace failed original relays with new Bosch relays or relays from other reputable automotive-grade manufacturers such as Tyco and TE. However, the wiring diagrams, amperage and voltage specifications printed on the original relays must be strictly followed when replacing them. Relays must be placed in the correct position as different types are not interchangeable. If relays with different internal circuits or inadequate volt/amp ratings are used, open circuits, shorts or other unpredictable behavior may occur. This may result in damage to other electrical systems. The internal circuitry of these boards is complex and connects the relays to each other in various ways, including coils being connected in parallel or series to multiple other switchable contacts and/or coils of different relays. As a result, even a single incorrect relay can cause multiple problems across seemingly unrelated electrical subsystems. If you are unsure what relay to use as a replacement, please contact us and we can advise you.
• 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 to boards, wiring or connectors even if the fuse does not blow. Replacing the fuse board will not stop the root cause of this problem, only make it less noticeable by reducing heat build-up in the fuse board 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, rough/seized mechanisms, clogged lines/filters, poor electrical connections and/or excessive current draw, replacing them as needed. We stock new replacement fan motors and fuel pumps.
• When replacing the fuse board you should inspect all associated wiring harnesses and connectors and repair or replace as needed. If the fuse board has failed, it is possible that there is additional damage to the plastic connectors, metal crimp-on terminals, and the wiring itself. We stock new wiring harness components, including both the white plastic connectors and crimp-on metal terminals.
• We recommend using Stabilant 22 on all electrical contacts when reinstalling your fuse board. This product forms a thin film on an electrical contact that becomes conductive when connected. Stabilant is used by many auto manufacturers on their electrical terminals. You can order this directly from the manufacturer or from many electronics supply retailers.

Support and Warranty

We provide technical support for all our fuse boards via email or phone. Please contact us immediately if you have any issue with fuse board installation. We take product support very seriously and have experts ready to assist you. Support requests are usually answered within 1 business day.

All our fuse boxes include a 10 year limited warranty, click here for full details. If you are experiencing an issue with one of our fuse boards, please contact us via phone or email for support and warranty instructions. Please do not ship a board back to us for warranty inspection unless instructed to do so, as we will first walk you through a troubleshooting procedure with the board installed in the car.

Ordering

Please contact us via email or phone for up-to-date pricing and lead times.

New board replacement kits are kept in stock and usually ready for immediate shipment.

If you would like your original board rebuilt by us, we recommend emailing or calling us first to confirm pricing and availability. Once you are ready to proceed, please ship your original board assembly to:

GT Car Parts INC
516 W. Lone Cactus Drive
Phoenix, Arizona 85027
United States of America

Please include a business card or note with your contact details inside the package. Remove all relays and fuses from the board before shipping, we do not need these for the rebuild process.

Once we receive the board, we will send you an email notification that it has arrived and is in the rebuild queue. Turnaround time varies based on workload but is generally less than 10 business days.

Important notice for international customers

We recommend international customers choose the board replacement kit rather than the rebuild service. The current tariff and customs processing situation in the United States adds unavoidable extra cost and delays to inbound international shipments. As the board replacement kit does not require you to ship your original fuse board to us, it is a much faster and more economical option for customers outside of the U.S.

For those international customers who wish to choose the board rebuild service, you must ship your fuse board to us using a “Temporary Importation Bond” or TIB. This requires you to file certain paperwork with your parcel carrier. Please contact us for further instructions before shipping. Any shipments sent to us without following the proper procedure may be delayed or incur extra fees.