[CrazyAirborne]

Ok so heres the deal. I have a US spec 2008 Escape. I say US spec because Im now living in the UK on a military assignment, and I need to add amber turn signals in the back. along with a fog light, but thats another question. Ok so me being all cool, I think, oh this'll be easy, Ill just splice the blinker wires on both sides, into the reverse lights, change the reverse lights to amber and BAM! yellow blinkers in the rear. I knew this would take away my reverse lights, but i figured I could deal with that later. Ok so heres the conundrum, the blinkers are also the brakes! now i dont see my own blinkers and brakes very often, but I knew they were the same bulb, but i figured they were on separate filaments, but sadly for my quick fix, they are the same wire, for the brake and the blinkers. So If I were to do my fix, every time i would hit my brakes, my blinkers would light up as the only brake lights. How can I fix this?! Is there a way to separate the two signals? If I cant fix this myself, I have to pay a shop to do it, and i assume this is going to be expensive. Anyone have any ideas? I looked at the wires down there for a trailer wiring, and it looks like these do the same thing, one wire for both the brakes and the blinkers. HELP ME!!!!! any thoughts are welcome!

 

[CrazyAirborne]

well I searched thru this site, didnt really find anything that could help me, so i googled a little bit more and found this on a ford focus site.

"run wires from the front turnsignals to the tails for a turn signal. Ran a wire from the third brake light to each tail and capped off the original wire altogether"

this might be my only option huh?

 

[jpark]

Well, sort of...

Just because it works on one car doesn't mean that another car is wired the same way, because newer Fords are wired very differently, but you can do that with a few modifications to their suggestions.

1) Each front turn signal bulb is driven by an individual transistor, designed for use with one bulb. Two bulbs will overload it to the point where the transistor will signal a malfunction to the Smart Junction Box and shut down that circuit to prevent overload damage.

2) You could get past #1 by using a relay coil in parallel with the front signal bulb (protect the SJB by connecting a 1N4002 diode across the relay coil, anode to coil ground, cathode/stripe to coil +), then using the relay to switch a rear bulb. But the Smart Junction Box will notice that the rear bulb is no longer connected, and you'll get hyperflash (very fast flashing). You'll also get a brake-lamp-out and/or a turn-signal-lamp-out warning in the message center, if you have one. The only way around the hyperflash is to connect a resistor or another hidden brake lamp bulb to the original rear lamp circuit (instead of just snipping it).

3) Running regular brake lamp bulbs off of the circuit for the high-mounted brake lamp is far too much current for the brake lamp switch and wiring to handle, and after the switch contacts arc for a few dozen brakings, they'll either stop working, or they'll weld themselves together and your brake lamps won't go out. Then the wiring to the high-mount lamp may heat up, since it's also not designed for that much current, and possibly melt the insulation and cause another short somewhere. The only way to run the rear brake lamps would be to switch them with a relay, where that relay coil is wired in parallel with the high-mount brake lamp. Also, protect the circuits in the car with a 1N4002 diode (as in #2) across the relay coil (anode to coil ground, cathode/stripe to coil +).

THIS IS WHY I THINK THAT ALL CARS SOLD IN NORTH AMERICA SHOULD HAVE MANDATORY AMBER REAR SIGNALS AND AMBER SIDE REPEATERS, just like the rest of the world!

Now that I'm done ranting, this project is not something that I would trust to an average dealer, especially if they don't have wiring diagrams. If they don't know what they're doing, or if they think that they can wire it as you suggested without any precautions (like the reverse diodes), they could cause damage, and it won't be cheap to fix the damage. Make sure that the relays are diode-protected, as I described, and that the coils are very low current.

 

[CrazyAirborne]

Well thanks for the heads up! This isnt what I wanted to hear, but I needed to hear it! This might be over my head... The shop deals with military people only, and they have to make all the US cars legal here, so hopefully they will know what they are doing. Im going to talk to them and see what they think.

 

[jpark]

Make sure that they know the following:

1) Front turn signal lamps and rear stop/turn lamps are individually controlled by high-side FETs, designed for one bulb each. Adding anything more than a fraction of an amp to any of these circuits may make the circuit report an overload to the Smart Junction Box, which will then shut down the circuit. I wouldn't add anything more than about 200mA to any of these circuits.

2) The brake lamp switch and the wiring to the high-mount brake lamp are not designed to carry more than about 2A. Adding two 2.2A 3157-style bulbs could cause switch contact arcing or wiring overload. Again, I wouldn't add anything more than about 200mA to this circuit.

Here's a good automotive relay that draws only 53.3mA at 12VDC and can switch up to 15A. It's designed for circuit board mounting, but you can still solder wires to the leads: http://search.digikey.com/scripts/DkSea ... 55-1240-ND

Here's a 1N4002: http://search.digikey.com/scripts/DkSea ... -TPMSCT-ND

Here's an example of a relay (controlled by a transistor) and how to connect the diode. This is only an example; just look at the relay and diode portion. You could use a 1N4001 diode, but in a car, I'd go with a 1N4002 just to be on the safe side. Make sure the diode is oriented correctly (stripe on the + side of the coil). And if someone tells you that you don't need a diode, go elsewhere. Switched inductive circuits can cause voltage spikes high enough to destroy a transistor.

 

[jr1]

DK if this is a bit late for you, but there is probably another way. RoadMaster sells a small device for use when towing your car with a motor home. It takes care of combined stop/turn to separate stop/turn. You could probably buy one on line and use it for this application well. It may be easier to reverse when you come home.