markg Posted May 9, 2008 Share Posted May 9, 2008 I've got an 87 Dolphin 900 and it's got a toggle switch that's wired to a blue plastic relay "Transmission relay - Toyota" The relay is about 2 inches by 3 inches and seems original. The toggle switch has a red lighted handle that goes hot with the ignition switched on (and with the toggle switched on). Anyone know what this is/does? Wild guesses appreciated too. Could the transmission cooler have an on/off switch?? Thanks much, Mark Quote Link to comment Share on other sites More sharing options...
markg Posted May 10, 2008 Author Share Posted May 10, 2008 figured it out....What it (red lighted toggle) does is ground out (through the lighted toggle) the blue (hot) lead coming into the transmission relay. This would have the effect (I presume) of defeating that relay which I suspect is linked to the high altitude sensor. Also, on closer inspection, the toggle is definitely aftermarket and the transmission relay is stock. So someone wanted to be able to defeat the high alt sensor with the flip of a switch. I'll confirm this on my first trip over Donner pass in a couple months. Does this make sense to you tech folks? - Or am I off base here? thanks, Mark Quote Link to comment Share on other sites More sharing options...
beehaven Posted January 16, 2009 Share Posted January 16, 2009 I've got an 87 Dolphin 900 and it's got a toggle switch that's wired to a blue plastic relay "Transmission relay - Toyota" The relay is about 2 inches by 3 inches and seems original. The toggle switch has a red lighted handle that goes hot with the ignition switched on (and with the toggle switched on). Anyone know what this is/does? Wild guesses appreciated too. Could the transmission cooler have an on/off switch?? Thanks much, Mark I had a transmission rebuild and the tranny man could not activate the transmission overdrive unit after he rebuilt it. His solution was to by-pass all the electronics with a toggle switch wired direct from the solenoid to the battery. That solution alarmed me so I took it to the Toyota folk who, (for a price), found two gaskets transposed in the valve body to be the problem. In a moment of frustration I almost went for the toggle switch solution. I suspect your's was to by-pass the temp. sensor or the altitude compensator which some folk have done to keep their overdrive working all the time. Quote Link to comment Share on other sites More sharing options...
powdrhound Posted January 17, 2009 Share Posted January 17, 2009 What drives this relay? Not the wire, but what/where is the device that picks up the elevation change - it has to be a pressure switch somewhere. Starting around 2,000', mine starts clattering like castinettes for the next couple thousand feet. Finally settles down and shut up. Overdrive stops at the beginning of the clattering. I have been considering installing a manual switch to override the relay input. I really don't need a relay to tell me that I am liable to lug the engine. Quote Link to comment Share on other sites More sharing options...
stacy Posted November 20, 2012 Share Posted November 20, 2012 Powdrhound.... I have an 86 sunrader that I am in the process of trying to figure out which way to go regarding the o/d bypass...I live in Taos, NM at 7500 ft so O/d is needed even just on the many flat, straight roads here. But everything you described is what happened to me as well when I recently transported my new lil rv here....lots of clicking from the relay switch and then since then no o/d. The mechanic is wondering exactly what you asked....where is the relay and what/where picks up the elevation change? Can you tell me more about what you did or how to exactly bypass? Thanks so much.... Quote Link to comment Share on other sites More sharing options...
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