cbpldc Posted August 27, 2015 Share Posted August 27, 2015 I've got a 1981 Datsun 280ZX automatic n/a. When I bought it, the blower motor didn't work, so I started chasing wires. I pulled the trim off the passenger side and noticed that the plug into the relay on the bottom of the blower motor was unplugged and that two terminals were jumpered. The blue/red and the red. Upon further inspection, the red wire had another wire tied into it about 3 inches away from the terminal that should have been plugged into the relay. So I followed that aftermarket wire to a toggle switch under the steering column and found that with the ignition on or off, it never had voltage. So I traced that wire that was supposedly feeding power to this aftermarket switch and it was tied into the green/yellow wire apparently coming out of the ignition switch in the column. It's likely that the load of the blower motor burned this out. The wiring schematic shows it going to a blue wire in the instrument panel. Does this mean I need to replace my ignition switch? Because it appears that it was used to send power to the blower motor switch. I also found that when I feed that jumpered terminal that goes to the blower motor some power, the blower fires right up and works. Does this mean that the relay or something upstream of the relay is bad? Part of what sucks about working on old cars is that you have to undo people's "fixes" to determine what the real problem is. Chris Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 27, 2015 Share Posted August 27, 2015 Looks like there are several components that could kill blower power if they failed. Probably not an ignition switch problem though because that would kill power to other important things. Quote Link to comment Share on other sites More sharing options...
cbpldc Posted August 27, 2015 Author Share Posted August 27, 2015 Well, yes, there's actually two different problems, one I was aware of, and another I located whilst troublshooting the blower. I'm primarily concerned about what the green/yellow wire does and why it no longer has power. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 27, 2015 Share Posted August 27, 2015 The wiring schematic shows it going to a blue wire in the instrument panel. Does this mean I need to replace my ignition switch? Because it appears that it was used to send power to the blower motor switch. I see it as splitting up to two locations, one a green/blue wire. No connection to the blower motor. But the diagram is hard to follow without losing track. Regardless, you're digging in to a problem almost nobody has ever had in an area nobody really wants to browse around in - wiring diagrams. Looks to me like it should only have power at Start though, maybe it switches off instrument panel power or lights something up. Not sure what R means, if that is an R. But, a look at the Starting section of the FSM might find something. Quote Link to comment Share on other sites More sharing options...
cbpldc Posted August 28, 2015 Author Share Posted August 28, 2015 I see it as splitting up to two locations, one a green/blue wire. No connection to the blower motor. But the diagram is hard to follow without losing track. Regardless, you're digging in to a problem almost nobody has ever had in an area nobody really wants to browse around in - wiring diagrams. Looks to me like it should only have power at Start though, maybe it switches off instrument panel power or lights something up. Not sure what R means, if that is an R. But, a look at the Starting section of the FSM might find something. I apologize if I'm not communicating clearly. The red wire that is connected from the green/yellow to the blower motor is something a previous owner added. it is not factory. I'm just concerned that the prior owner hooked this is up and that it worked for a while, and now it no longer does and I can't really tell what that green/yellow is supposed to be doing. The blower motor issue is actually pretty well documented, but I haven't gotten to the point of troubleshooting it yet. Thank you for taking the time to respond to my posts. Chris Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 28, 2015 Share Posted August 28, 2015 No apologies necessary. I was just pointing out how obscure your question is. In the picture I posted in #4 it shows GY (green with a yellow stripe) as a Start Circuit. I can't see why you would connect that to the blower unless you connected it to an NC (normally closed) relay that opened to cut off blower power. The GY wire is supposed to have power at Start only so you'd have to measure with a meter to know if it was working. Quote Link to comment Share on other sites More sharing options...
cbpldc Posted August 28, 2015 Author Share Posted August 28, 2015 Awesome! Thank you for your help! Quote Link to comment Share on other sites More sharing options...
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