Bones said:
You cannot reprogram an old remote or reprogram the system to recognize a new or used IR remote bought off e-bay or elsewhere the way you can for the radio freq type. The Dealerships used to say you had to replace both the transmitter and the receiver as a unit (>$400) because the IR freq has to match and is set by the board and not reprogrammable. The dealership units could not be purchased seperately so if dutchjeeps link is good for a replacement it would be great.
His link is good - I've been using a Piland remote for years now. I'd suggest that the original poster follow dutchjeeps' link to learn how to find the code in the receiver housing, and then get on the phone with Piland. They should be able to help him out.
Now, for those that are interested, I'm going to ramble on a bit about the inner workings of the remotes:
The issue with "reprogramming" the IR remotes isn't frequency. What happens inside the remote when you press the button is that you apply power to a cipher chip which generates a sequence of pulses that go out through the IR emitter diode. The pulse sequence generated is based on a set of tri-state inputs to the chipher chip (the states are high, low, and float), and by pressing the button you apply power to the chip and initiate the pulse sequence.
The receiver uses the same chip (it does both transmit and receive), with the tri-state inputs wired identically. However, instead of routing the pulse generator output to an emitter diode and only being powered when a button is pressed, this side is powered all the time by constant 12V off the vehicle battery. The IR sensor received the coded pulse sequence and routes it to the decode input pin on the chip, which then compares it against (I believe) an internally generated sequence based on its own. If the two match, it issues a pulse to the lock solenoids and the doors lock/unlock.
Where am I leading with all of this? It's that the the IR remotes are
technically reprogrammable, but they're not
practically reprogrammable. While the actual wiring changes are easy enough (though on the OEM style remote with its surface-mount components it's more difficult), determining the correct states of the ten tri-state inputs for the cipher chip is highly difficult.
The code on the receiver and transmitter is a 5-digit decimal number (values of 0 to 99,999). If memory serves, Piland's web sites states that there are a number of 5-digit codes that are, for reasons I can't recall, not valid. This means that the actual number of valid codes is somewhat less than 100,000.
Contrast that with the cipher chip. To generate the coded pulse sequence, it requires ten tri-state inputs. I seem to remember the data sheet for the chip saying that there were something like 30
million possible codes, and that one or two on either end were reserved. Now that I'm thinking about it again, I'll have to go find my OEM remote to get that part number so I can track down the data sheet again - it was interesting to read.
So you need to know how to decode the 5-digit code on the little sticker inside the receiver into the pattern of highs, lows, and floats for the tri-state inputs to the cipher chip to get your specific code to come out of the remote. I don't know how to do this, but Piland does.
Rob
