El Cheapo Heated Mirrors

[piercedtiger]

Originally Posted by george3

piercedtiger hope U can get all the bugs out so I can learn from your experience. Good Luck

lol Me too! I'm in no mood to take the mirrors off again and pull them apart to replace the pads. So I just put everything back together and said F-IT! Will see what happens when they frost over and I turn them on. On the way out of my barn I blew a fog light bulb too so I'm done for the weekend.


On a side note, I emailed the company I bought them from to see if they have any suggestions.

[shawnd2]

How did you wire them up?
+ve from the battery to the switch, then 2 +ve's (one from each mirror) to the switch. Then -ve's (ground) to a solid grounding point. Is it possible that you hooked the mirrors's up in series?
What is the resistance of each heating pad?
Do you have 12volts going to the switch, but then it drops going across under load?

Shawn

[CtryBoyInMT]

Originally Posted by piercedtiger

Does anyone have any ideas?

Pierced,

0.4v+ anywhere in the circuit is not right.

(I'm going to write a lot, but I just want to make sure when you do this I covered every possible scenario, so you don't have to wait for a reply )

Question: Are the grounds independently grounded in the doors or were they ran back into the cab and grounded together at the same point?

Before I'd tear apart the mirror's, I would make a double check that the switch is not at fault. Assuming you already verified that 12+ is getting to the switch, by-pass the switch by manually jumping the 12+ lead from the battery to the lead(s) running to the mirrors (ie: pull the two female spade connectors off the switch and temporarily complete the circuit).
This insures that 12+ is getting through the switch. If they work, the switch is faulty.

If not working:
Locate your grounds and make sure you have close to 0Ω (ohms) from the bolt to a known good ground. Some bolts I'm found are crap for a ground or paint is underneath them and don't conduct very well.

[To set your multi-meter up, put it in the Ω setting, hold the red & black tips together and set the zero with the adjustment wheel (make sure you use the correct scale when adjusting, unless you have a digital one, then it may do this automatically. Which tip goes where is not an issue.]

If the grounds were good, and still not working:

We isolated the fault somewhere between the ground point and the spade terminal from the mirrors on the switch.

Check the Ω's between the actual ground wire from one element (measure each independently is best) and the spade terminal from the mirrors that goes to the switch. You won't get 0Ω and I don't have an exact value, but we just want to see some movement in the needle or something besides "OL or Error" on a digital meter. They should also be similar in value.

Still no go:


You'll have to pop the mirrors out of the housing and using the points of the meter leads to pierce each wire about 1" from where they go into the element and make sure you have +12v at the element. (make sure the switch is on and stuff)

Final analysis:

If you ended up solving the situation at step one, awesome! If you got this far and still not operating, the elements don't seem to be functioning.

[CtryBoyInMT]

Shawn brought up a good point while I was typing my reply I didn't think about.

If they're hooked up in a series, I will have to add a few slight modifications to my diagnosis post. Although I would suggest rewiring to have them in a parallel circuit.

[piercedtiger]

Originally Posted by shawnd2

How did you wire them up?
+ve from the battery to the switch, then 2 +ve's (one from each mirror) to the switch. Then -ve's (ground) to a solid grounding point. Is it possible that you hooked the mirrors's up in series?
What is the resistance of each heating pad?
Do you have 12volts going to the switch, but then it drops going across under load?

Shawn

Originally Posted by CtryBoyInMT

Shawn brought up a good point while I was typing my reply I didn't think about.

If they're hooked up in a series, I will have to add a few slight modifications to my diagnosis post. Although I would suggest rewiring to have them in a parallel circuit.

Thanks guys! I knew someone would know more about these than me! I took electrical engineering in college a few years ago, but I'm very rusty on the formulas!

1. I have 12v, fused, from the battery (extra line I ran a year ago) to the switch.
2. 1 lead from each mirror soldered together, attached to switch.
3. other lead from each mirror soldered together, grounded under fuse panel. That bolt checked with a known good ground.

.....oh shit.... I just realized they COULD be in parallel... sumbitch.... Both leads are black, and I matched colors for the wires I added, but that doesn't matter now does it? It could be looping through both pads and back.....

That would probably explain the 348 or so ohms I got measuring from the + to the - over the mirror leads...

I think I'll try that tonight if I have time.

[piercedtiger]

ok.... my brain hurts... is it possible for them to be wired in series if one wire from each mirror goes to the switch, and the other from each mirror goes to ground? I know I don't one mirror wired to the switch with the second one wired to the ground side of the first mirror....

[piercedtiger]

blah.... I just remembered I tested each pad individually so it can't be a parallel vs series issue.... I left them grounded together, but separated the positive inputs. Same drop in in voltage with 1 as with 2 for both tests.

[CtryBoyInMT]

Originally Posted by piercedtiger

Is it possible for them to be wired in series if one wire from each mirror goes to the switch, and the other from each mirror goes to ground?

To answer the first question, No.

Originally Posted by piercedtiger

I know I [didn't wire] one mirror to the switch with the second one wired to the ground side of the first mirror....

Or both leads from one mirror are 12+ and both leads from the second mirror is ground.
I can not begin to count the hours I've spent tracking down a problem after I did that!!! Damn same colored wires. Pisses me off all the time.

[piercedtiger]

Originally Posted by CtryBoyInMT

To answer the first question, No.

Yeah, I was trying to picture the pads and the package in my head trying to figure out if it could loop through the pad somehow to have a polarity or cause them to be in series. I didn't think so, but I had just gotten to work and was still waking up.

And honestly I thought this was simple:

1. install pads
2. extend wires to driver side fuse panel
3. connect 1 wire from each mirror to ground
4. connect other wire from each mirror to switch
5. done, toasty mirrors on cold days
6. drink beer

Or both leads from one mirror are 12+ and both leads from the second mirror is ground.
I can not begin to count the hours I've spent tracking down a problem after I did that!!! Damn same colored wires. Pisses me off all the time.

Yeah, I used some left over trailer harness wire since I had a green/brown and a yellow/brown set. Still linked together so I could pull 1 wire, and separate the ends enough to connect everything.

What blows my mind is if either of the pads was bad I would expect the lighted switch to not light, and there to be no voltage drop. Like anything that could possible go wrong with this would open the circuit and shut everything down since it's basically just 1 big wire loop. No circuits, no moving pieces, no relays to go bad, no bulbs to burn out.... Just a fuse to blow and wires to break. Any of that would just open the circuit and not ground it so there'd be no voltage drop, no light on the switch, and a infinite ohm (1 on my digital MM) reading. The fact that there's continuity, AND voltage being lost SOMEWHERE leaves me perplexed. And slightly annoyed.

Oh, and I'm glad you figured out what I meant to type....

[CtryBoyInMT]

Jon,

I'm still pretty confident it's the switch.
No sense fretting until you confirm it's good by by-passing it.
Because whats the chances both elements being defective?

[piercedtiger]

Originally Posted by CtryBoyInMT

Jon,

I'm still pretty confident it's the switch.
No sense fretting until you confirm it's good by by-passing it.
Because whats the chances both elements being defective?

Yeah, that was my thought too. I find it hard to believe both were defective. I know the switch has 12v to ground on the pin the mirrors are plugged into, but it'll be simple to grabbed a jumper wire between 12v and mirror input to see what happens.

Although, if it's the switch I'm going to be equally pissed since it's wider than the other 3 similar switches I have, and I had to dremel out the blank. Small price to pay to get it working though if that's the case I suppose.

[piercedtiger]

Sonuvabitch!

You were right! I jumped it, and they got HOT within 30-40 seconds!



You sir are a genius! I tried another switch, and it worked with that too (although I'd jumped the first and middle pins a while back for some reason... )!

Pulled the original switch out, looked at the wire diagram again, and got them to work. Coulda sworn I had them wired the same way before, but now it doesn't illuminate. (Using the pic below I have to use the middle pin-acc on that one- and the ground to get them to work. Power and ground lights the switch, but doesn't heat the mirrors. I think there's a resistor between power and acc on my switch so I'm not sure what that causes.)

It's like this one with different labels for the pins. I hooked up the power and acc pins, but it doesn't light up. If I do the power pin it lights, but the mirrors don't work. Not something I want to leave as I'm afraid I'll leave them on (or the wife will). At least with a bright red light we'd be annoyed enough to remember to turn them off. I have it working for now without the illumination as I don't want to scrape the mirrors again in the morning, but I need to fix this soon.




Edit:

der....

So I need to run another ground wire. No big deal. Just do it this weekend or sometime this week when I have time.

Ok, doing it like this might help: (and help others doing this)

[bk1]

glad to see u got it up and running!!!!

enjoy the heated mirrors