I've got a Jwest fuse panel as well as the fog light flasher module that James makes. Both have been working great, but for whatever reason I keep popping the #9 fuse when the fog lights are on (the Jwest instructions say to attach the power wire for the flasher module to #9, but I think it should be #10, as per the wiring diagram). Car is a 1973 1.7.

After I swapped all of the wires over to the Jwest fuse panel in their existing order, some things didn't look quite right and didn't match up with the wiring diagram in Haynes - I think one of the POs must have changed the wire order at some point. I'd like to go back and check to make sure I have the correct wires in the specified spot. Can anyone tell me for sure, what side of the panel is supposed to be receiving power? I.e. if the panel is unscrewed and hanging down, should the side of the fuses closest to me be receiving power from the battery, or should it be the side toward the front of the car?

Pictures are a bonus. I'll try to take pictures of how it is currently and post them.

Is that fuse/wire controlling a relay through a switch to power the lights or does it go from the fuse panel to the switch which powers the lights? If it does the latter then you need to add a relay into the circuit. I'm not sure about which side a Jwest needs for power but if it is wrong I don't think it would be causing you to blow fuses. I suspect the fog lights circuit is drawing to much current for your fuse.

Jon

Its not that simple. On a '73, only one cable goes from the battery to the fusepanel, connecting to the rear of fuse 11 (reading left to right 1-12). That same wire powers the rear terminals of fuses 10-11-12 because that is the main power buss on the fusepanel.

Easy enough to compare your wiring connections to the factory schematic.

Thanks for the thoughts guys.

Jeff provided the information that I was trying to ask for. Unfortunately wiring is one of the hardest things for me to describe.

I saw in the diagram that #11 needed the power in from the battery and that it was split to #10 and #12. Just didn't know what side was power in on the panel. The Haynes manual didn't allow for me to determine which side was left/right, or front/back. Now that I have a reference point, I can check and correct the wiring order of the rest of them. I already know that the power in that should have been on #11 was on #12 (not that it really matters on that side of the panel).

After that, I can do a better job of figuring out what's going on with #9.

Well I tried rewiring things and went back and cleaned the grounds again, but I'm still popping fuses on #9.

Does not happen when the Pilot driving lights are on, or when the headlights are on with them. But if I step on the brakes with both of those on, it pops the #9 fuse. Which confuses me, because the only thing I have hooked up to the #9 fuse is exactly how this diagram looks:



On that note, what do the little numbers signify next to the wires coming out of the fuse box in that diagram? I.e. on the right side of fuse #11, there is a 7,8 and 10 for each wire.

Hoping James will jump in, as I know he designed a great product and knows our wiring very well.

The little numbers mean "go to the other page of the diagram and look for the same number, the wire continues there".

--DD

Check out your taillight assemblies. That is a common destination for headlights and brake lights voltages. Some corrosion there could cause weird things to happen.
What size fuse are you putting in #9? 5 or 10?
Tom

Under the conditions you are having the problem, you should be passing current through fuse #9 to power the brake lights, the fog light relay coil, and the dash gauges.

The brake lights draw about 4 amps. The gauges should be less than 1 amp.

The fog relay (we are only talking about the coil in the relay, not the fog light bulbs) should draw about 0.1 amp.

The fog light bulbs get their power from fuse #10.

The black wire from my fog module goes to fuse #9 because that is key-switched power, so the fog lights do not remain on when the ignition switch is off. Fuse #10 is hot all the time.

First thing is to get the wiring matched up; if you have something added to fuse #9 that is causing it to exceed the fuse capacity, then it needs to be addressed. Is the radio added in on this fuse?

If that is not an issue, then the source of the problem needs to be identified, which I would do by measuring the current actually drawn by each component attached to that fuse - ~4 amps for brake lights, ~1 amp for gauges, 100 mA for the fog relay, etc.

Thanks James, Dave and Tom. I'll look further into James' suggestions and troubleshooting advice. I'd like to get it wired back to the way it was supposed to be from the factory - upon starting the install of my Jwest components I didn't know that the PO must have moved a few things around.

That makes a lot of sense why you recommended the black wire be attached to #9 James. I certainly wouldn't have though of that.

Again, strange though because currently I don't have anything going to #9 but the two black wires on one side and the R/W, R/W, B/Y on the other side. Brake lights work fine otherwise, except the scenario I mentioned before.

James' kit calls for 7.5 and 15 amp fuses, and #9 *should* be a red 7.5 amp fuse. I haven't been able to find more 7.5 amp fuses locally, so I've been using a red 10 amp fuse. Even those blow though.

Hey James,
So nothing else is hooked up to #9, including the black wire from your fog light flash module - that's on #10. So basically #9 is hooked up completely stock. No radio, nothing.
The ONLY thing I can think of that is wired different than stock is the power wire to the HID relay (for HID lights). I jumpered the 12V power to the headlight motors to power the relay to avoid having to run 12V all the way up from the battery.

If I were to test for current draw from the brake lights, would I be measuring off of the black/yellow wire at the brake lights? Where would I measure for the gauges? And again for the fog relay? Thanks for your help.

#9 fuse should have a black/yellow and two red/white wire comming out of it. I believe the two reds are terminated together and the black is separate. If that iis the case, disconnect the reds and see if the brake lights still blow the fuse.

At least on my car, they're actually crimped together (I think from the factory). I could separate them and try that though.

I think that I've tracked it down to a problem between the fogs and the brake lights now. I put the fogs only on and held the brakes a little longer. Eventually the fuse popped again. As stated before, it does not do this when the regular lights and brakes are on together though.

Two things to remember here.
1- if you are using a multi-meter to measure your current levels, be very careful. You are blowing 10 amp fuses and most modern multi-meters fuse the current measuring circuit at 10 amps.
2- It is starting to sound if you have a light socket issue. Either corrosion or maybe one the previous owner hooked up backwards. If the socket itself is insulated from ground, you can hook up the wires either way with no problem and the light will still work. However if the socket ever gets grounded or partially grounded and you have the power hooked to the case side of the socket, then current will go way up, causing the fuse to blow.
Tom

agreed, light socket corrosion and grounds at the fog lights.

I clean the sockets with a dremel and the little assortment of round wire brushes.
Then put dielectric grease on the inside of the socket to help prevent it from happening again.

I had to do all of mine for the same reason...
lasted about 5 years now....

rich

Thanks guys. I had already cleaned the grounds for the tail lights previously including the sockets, but I supposed I could do them again.

Did not consider the grounds for the fog lights though. Those I need to check. So even though there is nothing from the fog light circuit connected to the #9 fuse anymore, a faulty ground on the fog lights could cause an increased load on the brake lights - enough to blow the fuse?

No Miata jokes this time Rich?

Mine was the sockets.....

Also, look at the wiring from the engine bay and how it routes back to the err drivers side lights....might be pinched at the engine lid intersection there....it's funky.

Also up under the rear valance inside the trunk..could be pinched.

The wiring is held in place by bent metal tabs that are supposed to have soft plastic covers on them, yet I find many that no longer have the protection....so this wear through....

Went back through the tail lights today before it started pouring rain. Cleaned all grounds and sockets with the lenses removed. Also found that the PO had a few wires mixed up from the way they were supposed to be. Bowlsby's site helped me out a lot with that one.

Unfortunately no difference, except this time the fuse blew with only the regular lights on when I hit the brakes. So I don't think I can isolate the fault to just the fog lights or headlights. It must be a problem with the taillights/brake lights.

I still have yet to try Rich's suggestions and look back through the trunk harness. That's next. I'll also pull the light housings apart and clean the wires/connections inside since I can't get to that stuff with just the lenses off. I also need to check the side markers since they were deleted by the PO but the harnesses are hanging bare inside the wheel wells. Something I've been meaning to take care of for awhile.

NORMALLY, I'd like to fix the problem. But what about using LEDs for just the brake lights if I can't solve this in time for the race in September. They draw a lot less current.

Scuze me...

Side markers and wiring first...
Seriously, look for all breaks, loose wires, shorts etc...
It's all physical and easy...just follow all the wires, check them for good solid covering.

Tape up the side marker light plugs...waterproof them..it's a very wet area.

Went back and re-wrapped the side marker wires that were loose before. I also, just for fun, swapped out the LED bulbs I got in the mail. No more popping of the fuse. Doesn't guarantee that I've fixed the problem yet, and as Rich said, I still need to find out what the real problem is/was, but at least I've found a workaround if need be. Thanks!

If led ligHts did the trick, you have corroded connections somewhere, or everywhere.

Most likely it's everywhere, sorry to say.

It's a milk crate, a Dremel with a wire brush, and some cleaner...and time.

Sit at the rear lights, pull all the bulbs and run the Dremel into each socket.
Clean every one.

Then pull the wires off the rear lights, clean all male and female spade bit connectors with the Dremel and some cleaner...do all of them.

Electricity on these cars is already stressed out on some of the circuits, so all the connectors need to be clean.
As you try to draw power through a corroded connection, it takes more power (amps) to draw that power through the connection, and that is why the fuse is blowing.

Led lights draw less power, so you have temporarily hidden the actual issue.
It will happen again as the corrosion gets worse, which it will, cause that is what corrosion does.

Just do one wire at a time, or use your phone to take a picture of the tail light wires before you unplug them....so you can get them all back correctly.
It's easy if you keep track, the rest is just cleaning, scraping, wire brush etc till you see clean bright brass again.

Petroleum jelly, like gasoline, does a great job of preventing corrosion from coming back.

While I was finishing up tuning the car today I decided to pull the bumper off and check the last grounds I hadn't cleaned yet - the fog light to body. Gave the mounting bracket and the immediate area surrounding the hole a good scuff with sandpaper, and a light coat of dielectric grease. Tried the fogs with lights on and everything seems good to go. I'll do a better test tomorrow when I get a chance to drive it around the block (having lights, fog lights and brake lights on all at once).

Nice to make some progress once in awhile. Thanks guys.