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Hey guys, I'd like to share my experience with you about replacing the battery fuse block boot.
My battery fuse block boot has been torn for 14+ years. I never thought about replacing it until I saw the @JP3 Motorsports part. I installed in today and I would like to share the experience. This how-to is for the stock location, so your mileage may vary.
1. Disconnect the battery and remove it from the engine compartment.
2. Remove the fuse block cover.
3. Remove 4 10mm bolts on the rear sides of the fuse block. These are the positive battery wires.
NOTE: The right side of the fuse block has 2 separate positive wires held in place by one 10mm bolt each. The left side of the fuse block has a wide terminal blade held in by 2 10mm bolts.
4. Rotate the fuse block about 90* counter-clockwise to access the 2 connectors on the bottom of the block.
5. Squeeze the latch on each connector to remove from fuse block. One connector has 3 pins and the second connector has 1 pin. They are fairly easy to remove.
6. The fuse block should now be electrically and physically disconnected from the positive wires.
7. Remove the 12mm nut from the positive battery terminal extension.
NOTE: This nut may be hard to remove. I chocked the extension in a vise and used a breaker bar to remove the nut.
CAUTION: It is possible to damage the battery extension if too much torque is applied or if it is not properly supported.
8. Open the narrow black access cover along the fuse block body.
9. Remove the terminal blade from the fuse block.
NOTE: This may be a good time to clean the internal metal components of the fuse block.
10. Remove the old rubber boot, or its remains.
11. Slide the JP3 Motorsports boot over the terminal blade using the "bottom" opening.
NOTE: There are 2 openings at the rear of the boot. A bottom and side opening. The terminal blade must be routed from the bottom.
12. Fit the new boot over the terminal blade so it appears to be fully installed.
13. Position the terminal blade with new boot into the fuse body.
14. It may be necessary to slide the new boot away from the bend of the terminal blade.
15. Once the terminal blade is in position to the fuse block, slip the rubber side opening over the black plastic shroud.
16. Close the narrow black access cover.
17. Install the positive battery terminal extension.
18. Position the fuse block near the positive wires and connectors previously removed from steps 3 and 5.
19. Reconnect the 3-pin connector and 1-pin connector to the underside of the fuse block. Press until the latches catch.
20. Reconnect the 4 10mm bolts, one bolt for each positive wire on the right side, and two 10mm bolts for the left terminal blade.
21. Reinstall the fuse block cover.
22. Perform additional battery maintenance procedures while removed - neutralize acids on the battery and terminals.
NOTE: This is a good time to install/replace battery terminal washers, aka battery @$$holes. They are either black and red or green and red. They help reduce terminal crud and corrosion.
23. Install and secure battery into position.
24. Reconnect battery terminals.
25. It's Miller time!
Here are some photos to help visualize the how-to. Old and torn boot on Positive terminal. Disconnect battery and remove.
Fuse block cover removed and right side bolts (2-10mm bolts) removed.
Left side bolts (2-10mm bolts) removed and terminal blade moved away.
Fuse block rotated 90* counter-clockwise to reveal the locking tabs. Press and pull the 1-pin connector.
Fuse block rotated 90* counter-clockwise. Press and pull the 3-pin connector out.
Fuse block removed from car.
Positive battery terminal extension chocked in a vise. USE CAUTION when applying torque to remove 12mm bolt!
Terminal blade removed and old boot removed. Note the narrow black access cover is open.
Side by side comparison between the OEM boot at JP3 Motorsports boot.
JP3 Motorsports boot partially installed on terminal blade. Note the narrow black access cover is still open.
JP3 Motorsports boot positioned over the terminal blade. Note the "side" opening.
The terminal blade and boot placed into the fuse block. Narrow black access cover still open.
Positive battery terminal extension installed and boot fitted around the angled housing of the fuse block. The "side" opening goes through this section.
All 4 10mm bolts reconnected to the fuse block. New boot open to reveal the positive battery terminal.
New boot in place and the fuse block is standing by for the battery to be reinstalled.
@Billy7, I did not investigate the positive wires further. Those wires in addition to the fuse box connectors are part of the wire harness. What did you do with the fuse block after relocating the battery?
*Break*
I did not mention this previously, but the red film on the positive battery terminal extension is battery terminal protector. It provides a barrier between the battery terminals and air to prevent oxidation and acidic crud build up. It can be found at most auto parts stores. It should be reapplied when contact is broken between the battery wires and terminals.
The fuse block is still there, I have to look into this, I don't have my car on me. It's the terminal blade that's sticking out that I want to remove. I haven't looked at where the 4 gauge wires (from battery) connect to in the fuse block.
You are always a wealth of information! Thanks for sharing the link.
JP3, thanks for the compliment!
My concern when removing the terminal extension is centered on damage to the fuse box housing. Torque applied to the nut is transferred along the extension through the terminal blade. The terminal blade then caused the fuse box housing to flex.
I monitored the flex of all parts while using a breaker bar then slowly applied torque to the nut. It was really on tight! It's safe to say that my fuse block was never disassembled in the car's 26 year history. That trend stopped yesterday!
Great write up! I bought this product a while ago. It’s a good supplement if your stock boot is ratty and you insist on having something over the positive terminal. That said, it does not fit well and was clearly not designed for this car. As the pictures indicate, the stock boot is offset while this one is straight; this results in tension on the boot and fitment issues that can not be remedied. It’s good enough and does the job, but a bit of an eyesore once you notice the poor fitment.
It’s described as a “non-OEM replacement,” however it is also listed as a Mazda RX7 FD3S Battery Fuse Block Boot, implying it was designed for this vehicle. When in fact, it was taken from another application and sold as an FD replacement part.
All that stated, it does work and cleans up the bay if you insist on having a boot there; additionally, it’s the best replacement option we currently have short of buying the entire fuse block. I just feel this is worth mentioning for those desiring an OEM quality replacement, which this is not. At one point there were product reviews indicating fitment issues, but they have since been hidden to prevent prospective buyers from seeing.
Last edited by 6speedrx; Apr 13, 2020 at 05:47 PM.
Great write up! I bought this product a while ago. It’s a good supplement if your stock boot is ratty and you insist on having something over the positive terminal. That said, it does not fit well and was clearly not designed for this car. As the pictures indicate, the stock boot is offset while this one is straight; this results in tension on the boot and fitment issues that can not be remedied. It’s good enough and does the job, but a bit of an eyesore once you notice the poor fitment.
It’s described as a “non-OEM replacement,” however it is also listed as a Mazda RX7 FD3S Battery Fuse Block Boot, implying it was designed in this vehicle. When in fact, it was taken from another application and sold as an FD replacement part.
All that stated, it does work and cleans up the bay if you insist on having a boot there; additionally, it’s best replacement option we currently have short of buying the entire fuse block. I just feel this is worth mentioning for those desiring an OEM quality replacement, which this is not. At one point there were product reviews indicating fitment issues, but they have since been hidden to prevent prospective buyers from seeing.
Thanks for the feedback. Fitment is not exact as the OEM unit as you state, though it is "good enough". We switched our eCommerce shop from GoDaddy to Shopify, and lost all of our reviews from the prior site due to the platform change. This had nothing to do with "hiding" negative reviews. I can link you to the old site which is still active until end of June and has all of our product reviews.
Thanks for the feedback. Fitment is not exact as the OEM unit as you state, though it is "good enough". We switched our eCommerce shop from GoDaddy to Shopify, and lost all of our reviews from the prior site due to the platform change. This had nothing to do with "hiding" negative reviews. I can link you to the old site which is still active until end of June and has all of our product reviews.
Thank you for the prompt response and clarification. It's good to know the lost reviews weren't a product of devious tactics, although unfortunately the end result is the same. I sincerely appreciate your transparency in the matter. I'll send a pm for the link, it would be helpful to substantiate the claim.
How-to: Battery Fuse Block Boot Replacement
