(ET) new relay in - now no reverse

[Michael S Briggs <msbriggs alberti unh edu>]

So I finally had time to put in a new relay in place of the blown
forward/reverse relay. Forward works fine now - even took it out for a
spin around the neighborhood. When I then went to back it into the garage,
I discovered that when I try to go in reverse, it goes forward. D'oh!
        My first thought was that I had hooked up the forward/reverse
relay wrong. I checked, and nope, it's fine. The problem is that the relay
isn't firing when I move the switch to the reverse-neutral side. I hear
the reverse microswitch click, but the relay doesn't move. Checked the
power connections on the relay, and it doesn't seem to be getting any 
power when I move the speed lever to reverse.
	Now, I suppose I could have just knocked something loose while 
fiddling with everything in there, but I'm wondering if there could be 
some greater problem going on that I'm overlooking (considering all the 
failures that I've had - while mowing last week, it stopped running - the 
control fuse had blown, and took out the fuse block in the process. 
Put in an inline fuseholder in place of the fuse block, with a fresh fuse, 
and found that I couldn't go forward due to a blown forward/reverse relay. 
Put in a new relay, and now the relay isn't getting voltage to fire. It 
seems like each time I fix one thing, something else breaks).
	After putting in the new relay, the first time I moved the speed 
control lever to reverse, I thought I heard the sound of something blowing 
- wasn't sure though if it was just the reverse microswitch clicking, or 
if something did in fact blow. It looks like control of the reverse relay 
goes through card#1 somewhere (still need to look over the schematics to 
figure out which "port(s)" on card 1, so I can see if something is just 
loose, or if something did in fact blow). I should be able to troubleshoot 
it ok, but what I'm concerned about is if there might be some greater 
problem underlying these little annoying problems. There have just been 
too many failures one after another for it to just be a coincidence, I 
think.
	Actually - if I had wired the power connections to the reverse 
relay backwards, what would that do? From looking at the relay, I assume 
it just uses a current through a solenoid to control a switch. If the 
current goes the wrong way, the B field would point in the opposite 
direction - but since I'm not sure exactly how it controls the switch, I'm 
not sure if that would be a problem or not, or if it could blow something.
        So, any tips anyone can offer (again) would be appreciated.

Thanks,
Mike

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Michael S. Briggs
UNH Physics Department
(603) 862-2828
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