Question Defrost on Mirrors

[JRJ04]

A while back, i wired up my mirrors so that the turn signal and side marker lamps would work, but chose not to wire up the defrost becasue i wanted to put a switch in so it wouldnt be on all the time. I didnt have a switch so i said "ehh...ill do it later." Well with the nasty humid winters coming on, I thought I'd go ahead and do it.

I followed the instructions below, except I wanted a switch. So, I tapped into the appropriate mirror wire on the passenger side, then ran it to the driver's side (so i would only have 1 switch for both mirrors). Then I found the driver mirror wire, and tapped it into the wire i had brought over from the passenger. At this point all I've done is tied the 2 mirrors together. Next, I found the power source per the instructions, tapped into it and then ran a line to my switch. So now on either side of the switch I had power and then the mirrors. I figured I didnt need to ground because the mirrors were already grounded from when I did the lights. Well, I got nothing. They just never would heat up.

So, I then said ok, maybe I need to ground them. At that point, I tied the power line and the line from the mirrors together so that they would be on one terminal of the switch. I then ran a ground to the other terminal. Turned the key on, flipped the switch...and within seconds it looked like a Snoop Dog concert in my truck...filled with smoke.

Whats going on here?

 

[BIG JOE]

Double Post JR.

If I'm understanding it all.. I think you had it wired right, before you grounded it all. One thing about those Heated mirrors, windows and such... they don't get Hot, or even warm to the touch.. They only get a bit warmer than the frost, or in time, ice.. Most are Timed, to only run for a period of time, based on the size of the window or mirror. That's been my experience with'm anyway

Anyone Else ???

Joe

 

[JLDickmon]

At that point, I tied the power line and the line from the mirrors together so that they would be on one terminal of the switch. I then ran a ground to the other terminal. Turned the key on, flipped the switch...and within seconds it looked like a Snoop Dog concert in my truck...filled with smoke.

Whats going on here?

you used the wrong switch.
you needed a double pole double throw if you were doing it that way..

personally, I would have switched the ground side only.

 

[dpantazis]

j: what was the wiring instructions you were referring to?
iirc, the two additional wires for each are ONLY for the turn signal and defrost heater. the two circuits use the existing ground for the mirror tilt and trim.

 

[BIG JOE]

personally, I would have switched the ground side only.

Me too.

 

[dpantazis]

personally, I would have switched the ground side only.

i dont think that you can, its a combined ground for all 3 circuits in the mirror.

 

[JRJ04]

TheDieselStop.Com - www.thedieselstop.com

Those are the instructions.

Ok so you say you would have only switched the ground? I'm not very knowledgable on electronics...So more explanation would help if you can.

So Joe, you think I had it right? The instructions just say that I should feel the heat on the mirrors.

If my grounding assumption was correct (meaning that the mirror is already grounded from when i did the lights) then am I right in having the mirrors on one side and power on the other? It just seems like it really kicked in when I grounded it the 2nd time. Did that cause some sort of feedback and burn up my switch? are both mirrors too much on one switch?

 

[dpantazis]

j:

dont worry about switching the ground for now. it does not apply to what you did or are trying to do.

what part of those instructions did you follow through? did you get the power tilt working? turn signals working? do you have marker lights? are they all still functioning?

where did you tap those connections to?

FYI- those defrost mirrors are always ON on the excursions.

dp

 

[JRJ04]

i followed all the instructions except for the defrost. everything else is working just fine. i didnt have to do anything for the electric adjustment because i had that on my old ones.

I followed the instructions for the defrost except I added the switch. I didnt do any additional grounding because I felt like I already had that covered when i did the lights.

 

[dpantazis]

j:

if you switched the only ground on the mirror, then NOTHING would work until you completed the ground path- no mirror adjustment, no turn signals, no nothing. OK? get it out of your mind for now.

FORGET about grounding for now, OK?

According to that writeup, using the colors that the author used for the heat function of the mirror, and what you described above, you should have had something like this-

DS--Light Blue Wire ----\

|-------- SWITCH---- KO+ power source----​

PS--Green Wire--------/

should have worked just fine. that is what you described correctly in part 1 or your original post.

"So, I then said ok, maybe I need to ground them. At that point, I tied the power line and the line from the mirrors together so that they would be on one terminal of the switch. I then ran a ground to the other terminal. Turned the key on, flipped the switch...and within seconds it looked like a Snoop Dog concert in my truck...filled with smoke."

what you did was connect the mirrors to the 12V supply wire, effectively making them constant on making the connection through the terminal of the switch.

then by putting a wire between ground and the switch, you created a direct path to ground- a short circuit. no different than a chaffed wire. hopefully you did nothing more than smoke that switch, the wire you installed from that switch to ground.

check for blown fuses. check for melted insulation on the wires you connected to.

good luck.