Possible cause for fusebox heating

[SteveJ]

A while back, I happened to search the web for specs on bulbs, in part trying to answer someone's questions on an electrical issue.

I have to confess that I have been lazy in calling out 1156 bulbs for side markers, license plate lights and rear markers. In the 74 FSM, Nissan called out the bulb specifications rather clearly. Type 67 bulbs should be used for rear/side markers, and type 89 bulbs should be used for license plate lights. I pulled up the 1156 specs today because I saw a comment on another thread talking about a fuse box heating up, so I made a spreadsheet to estimate the current draw. 

If all of the type 67 & 89 bulbs were replaced by 1156 bulbs, the current draw in the running light circuit would go up by approximately 12 Amps. That's more than double the draw of the factory specified bulbs. 

Check your bulbs to make sure you and previous owners used the appropriate replacement bulbs. If you want brighter bulbs, consider going with LED bulbs. The fuse box you save may just be your own.

Running Light Calculation.xlsx

[JSM]

Awesome info Steve. Thank you. That is a huge difference.