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#76
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REST switch
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BTW, does anyone know if the REST switch illuminates or otherwise indicates that the function is "ON"? Jeremy
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"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 Last edited by Jeremy5848; 01-20-2010 at 08:41 PM. |
#77
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Jay, ----------------- -1995 Blue W202 C36 AMG (M) SOLD ;( -1995 Black W140 S500 (Lady) -1992 Black W124 E300 (Dima) (Ex-Mosselman Twin turbo Kit). -1988 Black W124 300 E 4-Matic.(Nadeen) -1983 Brown W126 500SEL.(Old Lady)(Sold) -1981 Gold W123 280CE.(Dareen)(Sold) http://www.youtube.com/user/jayrasheed |
#78
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DC control of blower confirmed
Just confirmed that the blower control is a DC voltage between 1 Volt (low speed) and 6 to 9 Volts (high speed) on the yellow wire from the PBU to the controller module. The control current is almost negligible, less than 1 milliamp, so the controller must be a Darlington pair or an op-amp with a gain of 10,000 to 100,000. With 1 VDC control voltage, the blower runs at low speed, drawing 5 Amps from the battery. The air comes out of the defrost vents and the side dash vents, as I expected. Access to the wiring is at connector X64, located above and behind the power brake booster.
So the homemade REST circuit will work. I want to get out of this thread and let you go back to drag racing. I'll post a new thread in Tech Help or Diesel Discussion (since my circuit will go in my 300D) when I get a little farther along. The engineering is done; if I had a technician, I'd "leave the rest of the work to the technician." BTW, for folks who don't like the way the BPU controls blower speed, it would be easy to break the yellow wire at X64 and wire in a potentiometer to provide a control voltage between zero and about 6 Volts. Sixto, among others, is interested in this. Jeremy
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"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
#79
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Sounds good, Jeremy. If you could post a link here, when you get the new thread started, that would be great.
BTW - for drag racing purposes, I'd want a 10 minute limit on the REST function, 15 minutes maximum, and the blower on high speed. For the normap PBU operation, I'd like to have the "Auto" button converted to a "medium" speed, and sacrifice the "auto" function. I suspect Sixto was interested in the same thing. |
#80
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Great info, thanks!
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#81
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Bad news -- dealer says the part number is valid but they can't get it. Parts guy is someone I know and trust so it would indeed appear to be a non-USA part only. I'll have to try to get one, new or used, from someone in a country where 124s with the manual climate control were sold. In the meantime, I can use the rear window defog switch and just relabel it. Not as pretty but it will work.
For your drag racing purposes, you'd have to open up relay N10 and modify its timing constant from 30 minutes down to 10 or build your own timer with the appropriate time constant. You'd also need heavier wiring and a relay with 30 Amp contacts to run the blower at high speed. Otherwise it would be the same as my plan. Your idea can be done but would require a more detailed schematic of the electronics in the PBU than currently exists. The manuals I have show the PBU as just a box with a transistor symbol on it, the two cables with pinouts, and symbols for the pushbuttons and the temperature control dial. No inner circuitry. One would have to take the PBU apart and reverse-engineer it. Jeremy
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"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
#82
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I was thinking more along the lines of creating a timer/relay box that would turn on the aux coolant pump, and also turn on the HVAC fan on high, using diodes to prevent the accessory system from back-feeding into any of the factory electronics. I think the main hassle would be the 30A feed required, since the ignition switch kills power to the porcupine in the "off" position (at least, I'm almost sure it does - need to double check). At the track, I'm doing this manually by setting the temp wheel and fan speed both to "MAX" with the key on. Unfortunately, on a W124/M119 this pulls about 40A or so, since the engine computers draw a lot of current (MAF, etc). The REST setup should cut that by at least a third, maybe half if the fan speed was less than maximum. Hmmmmm.
Eric, I'd think you'd be interetested in this too! |
#83
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That might work. I haven't looked hard at the diode idea but it might work for the blower. The aux coolant pump is wired through the PBU and I don't know exactly how it is powered. A DPDT relay might be unavoidable there.
Yes, the blower controller's power is switched off by the ignition switch. The controller will draw a small amount of power even with the yellow speed-control line floating, i.e., at zero voltage. It draws enough current to make a tiny spark when power is connected to the battery via a clip lead. Enough that you wouldn't want to leave it connected all of the time. A diode in the main power lead to prevent back-feeding would have to be a healthy one and probably heat-sinked to boot since the blower can draw as much as 28 Amps at high speed. The voltage drop across the diode would also prevent the blower from reaching maximum speed in normal operation, probably not a big deal for most people. Jeremy
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"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
#84
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Yes I'm still here. I'm just not participating in the discussion because you guys have gone over my head now and I can't contribute anything useful. As you should remember, I'm just not that good with electrical stuff.
Yes, of course I'm interested. I just hope that whatever you guys come up with will be installable by regular folks like me and please, I would prefer not to have to give up any blower speed because when its warm I tend to run the "economy" setting on full speed to keep cool instead of running the air conditioning. Less heat for the engine and much less fuel economy penalty that way. (And yes, I leave the windows up.) Regards, Eric
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89 300E "Benzer1" 15.924 Uncorrected 93 400E "Benzer3" 14.200 U.C. 95 E420 "Benzer4" 92 300E "Benzer5" 16.299 U.C. Future turbo CNG 87 300D "Benzer7" 87 300D "Benzer8" 87 300D "Benzer9" 87 300D/70 AMC Javelin "Sidewinder-Benzer" 87 300TD "Benzer11" 06 E320 CDI "Benzer12" 05 E320 CDI "Benzer12A" 71 AMC Javelin AMX 401 "Sidewinder" 74 AMC Hornet 401 "C.K.10" 13.63 U.C. 74 Bricklin SV1 "Presto" AMC 360 pwrd. |
#85
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Plug and Play
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You'll need to make room for the switch to turn the REST function on and off; the wood panel that covers the ACC push-button unit and the row of switches above it is ideal but you'll need a panel with one more hole or sacrifice an existing switch and use its hole. You'll need a fused source of 12 volts, separate from any other source, directly connected to the battery, and a good connection to chassis ground, and a couple of other connections. You'll need a box with the relays and timer circuit. For those who are electrically challenged, I'd be willing to provide the design, gratis, to someone who wants to make a few bucks building the adapter. The box gets stuffed behind the dash wherever there's room. It won't be very big, say 4x4x3 inches or so. I'm currently searching for a source for the REST switch but a rear window defroster switch will also work. If it will quit raining, I'll hit the local Pick and/or Pull and get the parts I need to start building. Jeremy
__________________
"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
#86
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Are you in Temecula's wine country by any chance?
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89 300E "Benzer1" 15.924 Uncorrected 93 400E "Benzer3" 14.200 U.C. 95 E420 "Benzer4" 92 300E "Benzer5" 16.299 U.C. Future turbo CNG 87 300D "Benzer7" 87 300D "Benzer8" 87 300D "Benzer9" 87 300D/70 AMC Javelin "Sidewinder-Benzer" 87 300TD "Benzer11" 06 E320 CDI "Benzer12" 05 E320 CDI "Benzer12A" 71 AMC Javelin AMX 401 "Sidewinder" 74 AMC Hornet 401 "C.K.10" 13.63 U.C. 74 Bricklin SV1 "Presto" AMC 360 pwrd. |
#87
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Farms in Berkeley? Mooo!
I'm in Sonoma County. Been to Temecula, a warmish place to grow wine grapes, IMHO.
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"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
#88
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I'm not much of a wine person but I was hoping against hope that you were in that "wine country" since you were putting out a call for a gas W124 to try your device on a few posts back weren't you? I'm a lot closer to Temecula than I am to Sonoma.
Dave, I had to move around some stuff over the week-end and I came across the muffler and resonator that I had removed from Benzer 3 over a year ago. I didn't have time to weigh them but it's safe to say that I have found a fair amount of Benzer 3's missing pounds. Regards, Eric
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89 300E "Benzer1" 15.924 Uncorrected 93 400E "Benzer3" 14.200 U.C. 95 E420 "Benzer4" 92 300E "Benzer5" 16.299 U.C. Future turbo CNG 87 300D "Benzer7" 87 300D "Benzer8" 87 300D "Benzer9" 87 300D/70 AMC Javelin "Sidewinder-Benzer" 87 300TD "Benzer11" 06 E320 CDI "Benzer12" 05 E320 CDI "Benzer12A" 71 AMC Javelin AMX 401 "Sidewinder" 74 AMC Hornet 401 "C.K.10" 13.63 U.C. 74 Bricklin SV1 "Presto" AMC 360 pwrd. Last edited by 400Eric; 01-25-2010 at 10:27 AM. |
#89
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500E stock resonator + muffler = 49 lbs (resonator = 26, muffler = 23) On the 500E, a steel Y-pipe weighs about 10 lbs, for a 16lb savings. The 400E would have to have this welded in since there is no flange between resonator and muffler as on the 500E. I'll post photos on my website eventually. |
#90
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First steps
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This is my first step towards building a full-fledged REST function -- it confirms that the W124 blower control is pure analog and fairly easy to modify. My REST function will have a 30-minute timer at low blower speed while those of you who drag race want a 10-minute timer at a faster blower speed. For the latter I need to find another timer circuit. Hang in there while I do some more research. Jeremy
__________________
"Buster" in the '95 Our all-Diesel family 1996 E300D (W210) . .338,000 miles Wife's car 2005 E320 CDI . . 113,000 miles My car Santa Rosa population 176,762 (2022) Total. . . . . . . . . . . . 627,762 "Oh lord won't you buy me a Mercedes Benz." -- Janis Joplin, October 1, 1970 |
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