Brown Wire Mod??

Regan Burba · Dec 10, 2019

Hello everyone Happy Holidays. I had apparently “temporarily” fixed the headlight switch on my
87 X. I am going to have to replace it. The only one I have been able to locate is from a vendor often mentioned here. It is an earlier switch with a modified wiring harness to fit the 87. The switch is on the pricier side, not to the fault of the vendor, I’m figuring they are just hard to come by. I have read about the Panda switch conversion with relays, just not sure I want to go that route. It seems like a lot and my strengths are not in electric work.

I had taken apart a few switches I have and noticed the damage is primarily from the heat of the circuit. This has led me to start looking at the BWM and the headlight relay mod to decrease the load on the switch. I read the write up on Wiki by Bob Brown, it mentions the BWM going to the ignition switch. I have noticed in my car that the PO May have already done the BWM by sending the additional wire to the fuse box area. I have not been able to find instructions that explains how to do it this way so I am not sure what has actually been done. I have attached a few pictures of the battery and fuse box. In the fuse box photo where the brown wire and red wire merge the red wire goes to fuse box and the other brown wire goes to the harness into the dashboard. If you have clarifying questions regarding wires I can respond.
So my questions are...
Do I have the brown wire mod? If so would I follow the instructions on Wiki for the headlight relay mod? Would I add relay for just low beams as 87 Already has relay for high beams? Would I still benefit from running an additional wire from battery to brown wire in ignition?

bbrown · Dec 10, 2019

The wire as you show it is not what I would have expected to see.
The BBWM (as I call it) is essentially a "doubling" of the brown wire from the battery to the distribution post located at the lower left of the late model Fuse Block.

The reason for doubling the brown wire is due to the following factors:
1. The lone 10Ga Wire is not enough to carry the current necessary to adequately power the car & headlights & starter & wipers, etc. (properly)
2. The current drop of the wire -by itself- is excessive, partially due to the breakdown at the connection points, plus the gauge of the wire being too small.
3. The surface area of a single spade connector is not enough to adequately carry the current necessary, and over a relatively short time, degrades and heats up. (causing more resistance)

As designed, the ignition switch carries a huge burden because (electrically) it becomes the mid point to a wire that carries relatively high resistance.
Doubling the wire (thus increasing the wire size) from the battery to the fuse block actually moves the mid point of resistance away from the ignition switch.
Think of it like those old Bakelite Weller soldering guns that use the copper wire at the tip. The tip gets hot at the midpoint. Thicken one side of the wire and the midpoint changes.

But the BBWM mod also includes changing the ground wire as well. (I don't see it in your photo) You will need to get a 10" 4Ga ground wire replacement from battery to ground.
While you're at it, be sure the ground wire has a star washer underneath the terminal post-to-chassis to insure the connection bites into the metal underneath the bolt that holds it in place.
The above will cost you about $10 and will greatly improve your X1/9's electrical system.
Good luck!

Dan Sarandrea (Phila) · Dec 10, 2019

Unwrap that mess in the foreground, let's see what's lurking under the tape.

Eastep · Dec 10, 2019

Watching.

BTW We need a write up for 79-80 cars.

Tom Ginefra · Dec 10, 2019

Eastep said:
Watching.

BTW We need a write up for 79-80 cars.

BUMP!!!!!

lookforjoe · Dec 10, 2019

It looks like they just cut off the factory spade connectors at the relay/fuse box and tied the wire together, no wire has been added. Same at the battery - those clamp on terminals are essentially garbage - it will loosen & increase resistance over time - you really want a crimp terminal or even one of those solder-on terminals would be a vast improvement. If it separates whilst the engine is running you will kill the alternator, if not much worse.

Come down to Nyack sometime, I have the proper crimp tool for factory-style battery terminals

Dan Sarandrea (Phila) · Dec 10, 2019

Eastep said:
Watching.

BTW We need a write up for 79-80 cars.

I think I had this figured out, but we needed a 79-80 fuse box to confirm. Basically, the fuse panel has two categories of fused circuits, hot at all times and switched by the ig switch. The hot at all times circuits are mostly bussed together. The idea is to find an unused input connection on that bus and that's where you add the extra conductor coming from the battery.

If you really wanted to be slick, you could add a mongo relay to take the place of the ig switch in the switched circuit, and use the ig switch to power the relay as opposed to being the thing that carries the big load.

Or add smaller relays to selected circuits like headlights, wipers, starter, etc.

NEG · Dec 10, 2019

If the OP is just wanting to take the load off the the master switch and column switches for the headlights then install relays in the headlight pods and take a high current feed directly from the battery to the new relays keeping the original lighting circuit as a low current switching circuit to operate the relays.

Dr.Jeff · Dec 10, 2019

As NEG says, the brown wire mod is not going to specifically help with the headlight switch issue described in the original post....at least not as far as I understand these mods. However adding relays to the headlights will, assuming the headlights are drawing more amperage than the switch likes. In other words, they are two separate issues; both are great improvements and in my opinion both should be done. But realize what to expect from either mod so as to avoid possible disappointment later.

You mentioned a prior headlight switch fix. Was that a switch rebuild as others have demonstrated on the forum? Depending on the actual condition of the internal components in the switch, rebuilding the contacts and adding relays may do the trick.

Regan Burba · Dec 10, 2019

My goal is to decrease heat through the headlight switch and have headlights that are a bit brighter. I have a difficult time driving at night in this car (when the switch was working of course). It is to “my understanding” that the BWM may help with brightness and relays will help the switch.
The 87 slide switch has a contact slide for the headlight circuit that is misplaced due to the plastic being deformed from what I assume is heat. I have bent it back before but it did not last, I can’t think of a way to fix it. I have a toggle switch from an earlier car but has similar issues. I was out for a drive a few weeks ago and the lights went out at night. I want to get something reliable, especially since my son sometimes drives it.
In regards to what is going in my X right now I am still not clear if I have some sort of BWM or just an attempt. I have attached a few more pictures, Dan had asked what was under the taped wires and I tried to get a picture of the wires going into the back of the fuse box.

myronx19 · Dec 10, 2019

I have relays to take off the load off the key switch. I have a small fuse panel that handles four loads (headlights included). The third relay is for the radiator fan.

This is what it looks like underneath. I have a single relay for low beams, and a single relay for high beams. It's all fully tucked away as nice as possible, plug and play - no splicing. I have a connector that uses one of the OE headlight feeds to control the relays. The relays all have freewheeling diodes (internal). I bought all the parts from Digikey, and I have a terminal crimper.

I don't have a BWM on my car.

Dan Sarandrea (Phila) · Dec 10, 2019

OK if this is an '87, based on what we can see in the pix, you do not have the BWM done.

At the POS post of the battery, you have a big red, a smaller red, and a brown:

Big red: to starter
Small red: to FI double relay in spare tire compartment
Brown: to residential wiring wire nut as pictured

What you see at the residential wiring wire nut is what you would normally see at the 4-way connector that Bob Brown mentioned. It is a 4-way male spade connector in which all four male spades are bussed together. In the factory configuration three of the four male spades are occupied. Bob's version of the brown wire mod adds a second heavy conductor from the POS of the battery to that 4th unused position in the 4-way connector.

It looks like a PO had electrical issues centered around the 4-way connector, removed the 4-way connector and just ganged the three wires together with a wire nut.

NEG · Dec 10, 2019

Regan Burba said:
My goal is to decrease heat through the headlight switch and have headlights that are a bit brighter. I have a difficult time driving at night in this car (when the switch was working of course).

Then you need to put relays inline to the high current circuits and use the existing lighting circuit to switch those relays. I did this on my ‘78, the switches where dropping 2.5v across the circuit due to the high resistance of the switches and connections. Putting a relays in the headlamp pods with wiring direct from the battery improved the light output no end, if I can I’ll draw up a circuit of what (and I’m sure many others have done) of the connections....

Edit: just seen myronx19 post above, that’s 5he way todo it!

Dr.Jeff · Dec 11, 2019

Regan Burba said:
It is to “my understanding” that the BWM may help with brightness and relays will help the switch.

Actually headlight relays will help with brightness AND take the load off the headlight switch. They will specifically help the headlight circuit.
The brown wire mod is more to the benefit of the ignition switch and power supply to the fuse box, not specifically the headlights.
At least that is my understanding of it.

I think what you have on your car was a (failed) attempt to do the brown wire mod. I'd remove it and do it right, in addition to the headlight relay mod. I think I have some diagrams of these changes saved if that will help you.

Regan Burba · Dec 11, 2019

Thanks for all the responses. I agree that something may not be right with the present wiring. Dan mentioned what each wire off of the pos battery terminal was doing which is helpful. Is the brown wire coming from the battery factory or an add on? I can’t seem to locate a 4th spade connector on the fuse box to add to if I wanted to do the BWM correctly at the fuse box. There Are 3 separate connectors at the fuse box next to one another, with Red, red/black, and brown wires. The heavier red is attached to the 2 brown wires above with the connector. One going to the battery the other going to harness into dash. I’m wondering where the latter wire would be connected if it was not attached to the others.
I plan on doing the headlight relays. Would I just do the low beams on an 87 as I believe it has relay for the high beam already? Any diagrams you may have would be helpful.

Dan Sarandrea (Phila) · Dec 11, 2019

Regan Burba said:
Thanks for all the responses. I agree that something may not be right with the present wiring. Dan mentioned what each wire off of the pos battery terminal was doing which is helpful. Is the brown wire coming from the battery factory or an add on? I can’t seem to locate a 4th spade connector on the fuse box to add to if I wanted to do the BWM correctly at the fuse box. There Are 3 separate connectors at the fuse box next to one another, with Red, red/black, and brown wires. The heavier red is attached to the 2 brown wires above with the connector. One going to the battery the other going to harness into dash. I’m wondering where the latter wire would be connected if it was not attached to the others.
I plan on doing the headlight relays. Would I just do the low beams on an 87 as I believe it has relay for the high beam already? Any diagrams you may have would be helpful.

See this thread for pix of the original 4-way junction: https://xwebforums.com/forum/index....own-wire-junction-question.31455/#post-264037

Dr.Jeff · Dec 11, 2019

X1-9 Simplified HEADLIGHT wire diagram.png

Regan Burba · Dec 11, 2019

Wow, I can’t believe how far off my brain was on the wiring to the fuse box. The thread that Dan provided which showed how the power went to the fuse box cleared things up.
Both My 87 and an 86 parts car do not have the 4 way spade connectors in them,so I was thinking something very different. It appears that to clean this up, and likely add another wire from battery to fuse box I need to find an alternate way of joining the wires that are now connected with residential wire twist. At the same time leaving room to add the additional wire. I think I want to use something different than the original 4 way connector.
As recommended I will also do something different with the wires at the battery terminal and improve the neg cable.
A lot of info was provided to me regarding the headlight relay mod, I should be able to get through that OK. If not I’ll reach out.
thanks for all the assistance.

Dr.Jeff · Dec 11, 2019

Regan, you bring up a good point about the various BWM's.

Ideally the new larger gauge, heavier capacity power lead coming directly from the battery would connect directly to the main power terminal on the fuse box itself. However as you have found there isn't a convenient way to make that final connection on many of these wire harnesses/boxes. The fuse box does not have a big threaded terminal that the power lead connects to or something similar (as some other older vehicles have). So where/how do you splice into the fuse box? By making a splice into the existing wire (like the prior owner did to your car), it is only as good as that final few inches of original wire into the box. That will be the weakest link. Granted it is still better than no additional wire, but the current must still pass through the smaller gauge wire for that final short stretch. Sort of like increasing the water pipe diameter throughout your house but not the increasing the size of the main shutoff valve (that may be a bad analogy, I'm not a plumber, but hopefully you get the idea).

The same is true for the wire upgrade at the ignition switch. Adding a new larger gauge power feed to the switch, but not being able to connect it to the actual terminal in the switch. Instead having to splice into the existing smaller wire somewhere near the switch. Better than nothing, but not ideal.

I suppose the only true solution might be to replace the entire fuse box with a better design, and same for the ignition switch. And some have done that. But most of us do not want to go that far. I guess the best we can do is make our best effort to improve the power feeds to the critical components in the best possibly way. And that may mean splicing into the original wire as close as possible to the final component. For such a wire splice, a soldered connection might be good (although some prefer crimp connections for everything). Personally I remove the existing original wire and splice my new large gauge wire to the little pigtail I've left at the fuse box. But some prefer to leave the original wire and add the new lead as a second feed to that point. It might depend on what gauge of new wire you choose.

If you wish to connect multiple main power feeds - i.e. a large gauge wire from the battery, a large wire to the ignition switch, and a large wire to power an auxiliary fuse box (for additional circuits and relays), then maybe consider using some sort of buss bar or power terminal. Here are a couple examples:

And at the battery post you have a few options:

One method I like to use for the battery is installing a side post battery (with the threaded holes rather than large posts) so I can bolt several battery cables onto the same point (using cables with a eye ring lug on the end instead of a clamp). But the "marine" type of top post clamp with the threaded stud and wing nut (bottom left image) will do the same.

dllubin · Dec 11, 2019

Dr.Jeff said:
Regan, you bring up a good point about the various BWM's.

Ideally the new larger gauge, heavier capacity power lead coming directly from the battery would connect directly to the main power terminal on the fuse box itself. However as you have found there isn't a convenient way to make that final connection on many of these wire harnesses/boxes. The fuse box does not have a big threaded terminal that the power lead connects to or something similar (as some other older vehicles have). So where/how do you splice into the fuse box? By making a splice into the existing wire (like the prior owner did to your car), it is only as good as that final few inches of original wire into the box. That will be the weakest link. Granted it is still better than no additional wire, but the current must still pass through the smaller gauge wire for that final short stretch. Sort of like increasing the water pipe diameter throughout your house but not the increasing the size of the main shutoff valve (that may be a bad analogy, I'm not a plumber, but hopefully you get the idea).

The same is true for the wire upgrade at the ignition switch. Adding a new larger gauge power feed to the switch, but not being able to connect it to the actual terminal in the switch. Instead having to splice into the existing smaller wire somewhere near the switch. Better than nothing, but not ideal.

I suppose the only true solution might be to replace the entire fuse box with a better design, and same for the ignition switch. And some have done that. But most of us do not want to go that far. I guess the best we can do is make our best effort to improve the power feeds to the critical components in the best possibly way. And that may mean splicing into the original wire as close as possible to the final component. For such a wire splice, a soldered connection might be good (although some prefer crimp connections for everything). Personally I remove the existing original wire and splice my new large gauge wire to the little pigtail I've left at the fuse box. But some prefer to leave the original wire and add the new lead as a second feed to that point. It might depend on what gauge of new wire you choose.

If you wish to connect multiple main power feeds - i.e. a large gauge wire from the battery, a large wire to the ignition switch, and a large wire to power an auxiliary fuse box (for additional circuits and relays), then maybe consider using some sort of buss bar or power terminal. Here are a couple examples:

View attachment 27923 View attachment 27924

And at the battery post you have a few options:

View attachment 27925 View attachment 27926 View attachment 27927 View attachment 27928

One method I like to use for the battery is installing a side post battery (with the threaded holes rather than large posts) so I can bolt several battery cables onto the same point (using cables with a eye ring lug on the end instead of a clamp). But the "marine" type of top post clamp with the threaded stud and wing nut (bottom left image) will do the same.

The goal is to reduce the series resistance. Although the fuse box may not have a big terminal to connect to, splicing into the existing connection is not that terrible because the small diameter wire is now very short. Resistance of a wire is a function of resistance per unit length and the overall length. Therefore, you can reduce resistance per unit length (larger diameter wire) and/or reduce length to reduce overall resistance.

Brown Wire Mod??

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