Charlie69 Posted January 3, 2015 Report Share Posted January 3, 2015 I have noticed that there have been a few requests for fuse blocks for the 521. As far as I know there are 2 types, I have spent a couple hours searching for a good replacement and this is what I came up with. The Blue Sea 5035 http://www.powerwerx.com/fuses-circuit-protection/blue-sea-5035-6-independent-circuit-fuse-block.html By using these Blue Sea 9217 jumpers this fuse block can be jumper to match either 521 OEM fuse block configuration. https://www.bluesea.com/products/9217/Terminal_Block_Jumper_for_30A_Terminal_Blocks Blue Sea 9217 2 Quote Link to comment
DanielC Posted January 3, 2015 Report Share Posted January 3, 2015 This might be a good option, also. http://www.summitracing.com/parts/prf-70207/overview/ The current for all the accessories goes through the ignition switch on a stock 521. Although I have not done it, it seems to me that the summit fuse block, with a relay switched by the ignition may remove electrical accessory load from the ignition switch. I also have found the two different types of fuse block, 3 always hot, and 3 switched, and the 4 - 2 variety. An easy to do fix is to add an extra relay to supply power to the stock headlight relay. Power this extra relay from the battery, or battery side of the stock fuse block, or starter. Use a fuse, of course. Pull the red with yellow stripe wire off the stock headlight relay, plug that wire to pin 86 of added relay. Supply power to pin 30 of added relay, explained above. Ground pin 85 of added relay. Connect pin 87 of added relay to the open connection of the stock headlight relay. This modification removes headlight current from the stock fuse box. Because the headlight current no longer has to go into the cab, and stock light switch, and back out of the cab, through several connectors, the headlights also get more voltage. 1 Quote Link to comment
Charlie69 Posted January 3, 2015 Author Report Share Posted January 3, 2015 I looked at the Painless one one. The Painless is $86 the Blue Sea is $36. The Blue Sea is designed for marine use. The Blue Sea is simple enough that a layman can change it out. Other than drilling 1 new hole to mount it and using the jumpers to configure 1 of the 2 different blocks used on the 521 it is a matter of taking the wires 1 by1 of the old fuse block and screwing them onto the Blue Sea Block. The most important criteria I was looking for in a fuse block was easy to install and durable. As for all the points your are making DanielC are valid points. I feel that wiring is over whelming to a lot of people so the easier the better. Adding circuits and relays is not for everyone. These little Datsun cars and trucks have run many years without being re-engineered electrically and will run many more years without the electrical improvements. I am saying that doing these electrical upgrades are a benefit only if done correctly by a person that understands what they are doing. Keep it simple. DanielC looking at Painless fuse block it appears that it has a relay built in to and is rated at a total of 30 amps. Not enough for all the circuits in a 521. So in order to use it you would have to run additional fuses and relays to make it work safely. Please correct me if I am wrong. 1 Quote Link to comment
DanielC Posted January 3, 2015 Report Share Posted January 3, 2015 As far as I can tell, the Painless block has three fused constant hot circuits, and four switched hot. The 30 amp relay only handles the current for the four switched hot circuits. The stock 521 fuse block has either two ignition switched hot, or three ignition switched hot circuits I have not actually tested this, but I believe the Datsun 521 ignition, and crank circuits are not fused. The headlights, park lights, side lights, tail lights, hazard lights, stop lights, and horn are fused, but constant hot. Turn signals, reverse lights, wiper, windshield washer, heater, instrument panel, and radio are fused, but switched by the ignition switch. So is the stock system of switches, and relays that retard the timing, and activate the solenoid on a stock Hitachi carb This is the load the 30 amp relay would handle. The stock headlights, on high beam use about 15 amps. This is a picture of a replaced fuse box in Dragon. This was done around 1980, and the truck was daily driven into the early to mid 1990's. This truck also had a 60 amp external regulated alternator, and an amp gauge. Amp gauge installations are not done as often now, because the amp gauge requires wiring to and from the gauge that will handle the full output of the alternator, to the gauge, and back out to the fuse block. You can see a copper buss bar tying four fuses together, these are the constant hot fuses. The two other fuses are tied together with the short black wire loop. There is some extra wiring for an brake controller on this truck. This truck also has Cibie quartz halogen headlights, on a separate headlight relay. The stock headlight wiring was used for the two outside headlights, and the extra relay handled the electrical load for the inner headlights. I may of also ran some fog lamps on this truck, it is hard to remember the exact details of wiring I did on this 35 years ago. 1 Quote Link to comment
Charlie69 Posted January 3, 2015 Author Report Share Posted January 3, 2015 You are correct DanielC. What I cannot find on the Painless Block is the gauge of the main feed wire. The thing I do no like about the Painless block is the pigtails hanging out which means you have to splice the wires to it. The Painless block is designed as an add on block for additional accessories. This does not mean ti will not as a great fuse block for these little cars and trucks. My personal experience with Painless products are they are quality built and well engineered products. DanielC you have a great understanding of the wiring on the trucks and I appreciate you adding to this thread. The only way I would suggest the Painless block to the public is to include a how to on installation with a wiring diagram included. Quote Link to comment
a6m-zero Posted January 3, 2015 Report Share Posted January 3, 2015 I'd be really interested in this if you go for it! 1 Quote Link to comment
Charlie69 Posted January 4, 2015 Author Report Share Posted January 4, 2015 I do not think I will have time to do a Painless write up and wiring diagram. I suggest at this point using the Blue Sea System Fuse Block. I personally use a 720 harness when rewiring a 320, 520, 521 trucks as a lot of the items mentioned by DanielC is already incorporated in the 720 harness. If you read through my build thread on my 520 you will see where I adapted the 520 521 instrument cluster to the 1980 720 2WD L20B automatic transmission harness. Every chance I get to pull a 720 harness I do it even if it is chopped up. I can use the circuits in something. Quote Link to comment
DylanLes Posted April 5, 2017 Report Share Posted April 5, 2017 I'm thinking about buying a NILES OEM fuse box for my 521 I saw on eBay. It's new in the box. Do you guys recommend this? 1 Quote Link to comment
d.p Posted April 5, 2017 Report Share Posted April 5, 2017 Yo man, I bought that one from Australia, same one? You got a J13 or L16 motor because that one is for a J13 but you can make it work if you have the right (l16) fuse box. Just need to switch the hot and switched fuse bars (pop them out from the bottom) from the old to new. Also the label won't be right. But if you have a J13 have at it. J13 on the left and L16 on the right. Fuses for L16 are 10,15,10,15,15,15... 1 Quote Link to comment
DylanLes Posted April 5, 2017 Report Share Posted April 5, 2017 I'm looking at one from Thailand, I have a J13. Seem right? 1 Quote Link to comment
d.p Posted April 5, 2017 Report Share Posted April 5, 2017 IDK because that fuse box looks different than the J13 fuse box I posted above you. Does that match your current fuse box? If so you should be OK to proceed. 1 Quote Link to comment
yenpit Posted February 9, 2020 Report Share Posted February 9, 2020 Old post, but what was the outcome? I've got a 1972 521, working on electrical, want to replace fuse box. Currently there is another OEM Niles fuse box on eBay out of Thailand, but it too is NOT the same as mine. Reading thru Chrlie69's post now, so might go Blue Sea fuse box & modify as instructed......... 1 Quote Link to comment
Greaser2 Posted February 9, 2020 Report Share Posted February 9, 2020 13 minutes ago, yenpit said: Old post, but what was the outcome? I've got a 1972 521, working on electrical, want to replace fuse box. Currently there is another OEM Niles fuse box on eBay out of Thailand, but it too is NOT the same as mine. Reading thru Chrlie69's post now, so might go Blue Sea fuse box & modify as instructed......... I bought the wrong Niles and switched just the terminals from my original needed to the new Niles then made up a new label 2 Quote Link to comment
yenpit Posted February 9, 2020 Report Share Posted February 9, 2020 The brass crossovers on the bottom are different on the Niles fuse box that is currently on eBay. Am I seeing that you SIMPLY swapped the RED BLACK with the BLUE RED terminal to terminal? As far as I can see, the rest of your wires match mine............. 1 Quote Link to comment
mainer311 Posted February 10, 2020 Report Share Posted February 10, 2020 I highly recommend getting away from glass fuses, unless you want to keep it original. 1 1 Quote Link to comment
thisismatt Posted February 10, 2020 Report Share Posted February 10, 2020 Glass fuses are kind of like me - usually appears good on the outside, crumbling and disfunctional on the inside. 2 Quote Link to comment
mainer311 Posted February 10, 2020 Report Share Posted February 10, 2020 Dark. 1 Quote Link to comment
d.p Posted February 10, 2020 Report Share Posted February 10, 2020 1 hour ago, Greaser2 said: I bought the wrong Niles and switched just the terminals from my original needed to the new Niles then made up a new label Nice man. glad I could help you figure it out. Got an extra label by chance? 1 Quote Link to comment
d.p Posted February 10, 2020 Report Share Posted February 10, 2020 (edited) 1 hour ago, yenpit said: The brass crossovers on the bottom are different on the Niles fuse box that is currently on eBay. Am I seeing that you SIMPLY swapped the RED BLACK with the BLUE RED terminal to terminal? As far as I can see, the rest of your wires match mine............. Pretty much. Just take your terminals from your existing one and put them in that Niles one. It’s what I and greaser2 did. Edited February 10, 2020 by d.p 1 Quote Link to comment
Greaser2 Posted February 10, 2020 Report Share Posted February 10, 2020 (edited) 3 hours ago, yenpit said: The brass crossovers on the bottom are different on the Niles fuse box that is currently on eBay. Am I seeing that you SIMPLY swapped the RED BLACK with the BLUE RED terminal to terminal? As far as I can see, the rest of your wires match mine............. Yes. Like DP, u pull out the terminals and switch. Only need to switch the the one side. It’s a little tricky pushing them out but once you figure it out it’s easy. Edited February 10, 2020 by Greaser2 Edit 1 Quote Link to comment
Greaser2 Posted February 10, 2020 Report Share Posted February 10, 2020 2 hours ago, d.p said: Nice man. glad I could help you figure it out. Got an extra label by chance? yes, it’s a word doc I can send you. IM me your email. Just print on a thick stock. 1 Quote Link to comment
d.p Posted February 10, 2020 Report Share Posted February 10, 2020 12 hours ago, Greaser2 said: yes, it’s a word doc I can send you. IM me your email. Just print on a thick stock. Messaged you my email, thanks buddy. 1 Quote Link to comment
d.p Posted February 10, 2020 Report Share Posted February 10, 2020 Put it up on the internet if anyone needs or wants it: 521 Fuse Box label: https://drive.google.com/open?id=1yi28N8Wx1WGJKqCK_53h2VtUkXwPNGP- 2 Quote Link to comment
DanielC Posted February 10, 2020 Report Share Posted February 10, 2020 (edited) I put this fuse block in Dragon, in 2015. It is a Blue Sea systems ST blade fuse block, their part number is 5035. You will also need Blue Sea systems terminal block jumpers, part number 9217. Another picture. Right now, I am running Dragon without a dashboard. There are also some extra wires going to the fuse box, to accommodate an ammeter. The light is also wired to the switched hot side of the fuse box, to power the alternator. Pay no attention to the fuse values. With no dashboard in the truck, the fuses are not hooked up to anything. By the way, a Datsun 521 will run without any fuses in the fuse block. This is how I mounted this fuse block in Dragon, the name for this truck. The Blue Sea fuse block was not secured in the truck, yet. I did not want to drill more holes in the truck, so I used a piece of ABS plastic to hold the fuse block. The two countersunk holes match the spacing of the original 521 fuse block. The metal inserts are "T" nuts. The back side, showing the "T" nuts. Flathead screws used to hold the ABS plastic to the cowl. The ABS plastic piece screwed down. The fuse block screwed to the ABS plastic. Edited February 10, 2020 by DanielC 3 Quote Link to comment
Thirty Posted March 17 Report Share Posted March 17 Hey everyone, I have a 1970 Datsun 521. It has a modern fuse box conversion and it’s vertical in engine bay. Second to last fuse is a 25amp and it keeps melting. It’s the main power fuse for the Datsun. So when it burns out the entire Datsun loses all power and cannot drive anymore until replaced or jump wired. What should the amp be? And any ideas on cause? -Thirty Quote Link to comment
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