Topic: FTDRL Question

[Main One]

I followed the DIY in the lighting mod section. Used the exact same materials  and method. I have had them in for 15 months now and have never ran into a single issue. Not saying you don't know your stuff. Just stating that I haven't had any issues. (Knock on wood you have me a little paranoid now lol)

SENT FROM MY EVO 4G

You motivated me to look at the write-up. 

From looking at it I can't be sure just by what's there, but I'm assuming that the diodes are passing current needed to switch the relays and not the current going to the lights.  In that case the use of a small signal diode vice a power diode should work fine per your experience.  As OBB noted, it is a different setup for the newer trucks, and when I saw you recommending a small-signal diode for a power diode I became concerned.

[Al]

You motivated me to look at the write-up. 

From looking at it I can't be sure just by what's there, but I'm assuming that the diodes are passing current needed to switch the relays and not the current going to the lights. In that case the use of a small signal diode vice a power diode should work fine per your experience.  As OBB noted, it is a different setup for the newer trucks, and when I saw you recommending a small-signal diode for a power diode I became concerned.

Is this reply for PBO, our for mine? Should I switch diodes for the fogs on high? The way I have it set up is that the fogs are on fulltime, with the headlights on low and high. God knows I need to burn the Av to the ground and it parks next to the house!! Deb would be chasing me down the street. 

[Main One]

Is this reply for PBO, our for mine? Should I switch diodes for the fogs on high? The way I have it set up is that the fogs are on fulltime, with the headlights on low and high. God knows I need to burn the Av to the ground and it parks next to the house!! Deb would be chasing me down the street. 

That was for PBO.

The 3A/50v versus 3A/40v diodes you were asking about are both power diodes.  You wouldn't normally replace either one with a 1N914 diode which isn't sized to take 3A of continuous current.  I wouldn't think a diode in your application would be needing to hold back current at 30v of "pressure", much less 40 or 50.

[Al]

Thanks MO.

I used the 1N914 for the fog light mod, as per another forum. At first, I wasn't worried about that, but a question came up during this thread. Should I change that to to a 3A/40V power diode?

[Main One]

Thanks MO.

I used the 1N914 for the fog light mod, as per another forum. At first, I wasn't worried about that, but a question came up during this thread. Should I change that to to a 3A/40V power diode?

Not knowing what you've done, I'll have to give a somewhat generic answer which is it depends.

What it depends on is what current is flowing through the diode.  If it is the relatively much lower level of current which "turns the relay on" then the 1N914 should be fine.  If it is the much higher level of current going to the lamps coming out of the relay, then you would need a power diode.  Note that one could connect a small-signal diode to the wiring going to the headlights such that when they were on it would trip the DRL relay, but it would be better to connect that diode to the lines used to control the relays from a possible over-current protection point of view.  That's because the wiring to the lights should be able to handle the amount of current that the fuse for that circuit would handle before blowing, but the small signal diode, and quite possible the smaller wiring used with it, wouldn't be able to handle that much current should a short occur on the other side of it.

[Al]

I think I have it right but here's a picture. Not sure if this is going to help.

The power diode goes from right side of the 15 A fuse to the top left of the headlight relay. The 1N914 diode goes from the black fog lamp relay to the bottom left of the headlight relay.

[Main One]

I'm not familiar with the relays and their orientation in the new trucks to be able to tell anything from your pictures.

Most automotive relays have a diagram printed on them similar to the below.  The current going through pins numbered 85 and 86 in this diagram are going through the relay coil - that current is the low-level control current which switches the pole connected to pin 30.  Pins 30, 87 and 87A can carry the current that the relay is rated for.  The 1N914 diode should be able to handle the current going through 85/86, and most if not all other automotive relay coils.  If connecting to the other power-handling pins, I would want to either fuse-protect a 1N914 (assuming it was connected at the other end to another relay's coil pin) or use a suitably-sized power diode.

[Al]

OK, believe I have it right then. Thanks again.