[TR] TR4 wiring

Randall tr3driver at ca.rr.com
Thu May 28 21:43:07 MDT 2009


> 1) My fuse box disintegrated.  Should I use an original type 
> replacement or is there an advantage to using an upgraded blade type? 

IMO, an original style in good condition is perfectly adequate.  The main
advantage of 'blade' type fuses is that they are small and cheap.

> If I upgrade what exactly do I need? Know any sources for these?

If you really want blade type fuses, then something like this
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330333247391
would work well.  But I have to say that, IMO, an electrical neophyte would
be better off sticking with the stock setup.  Note that your replacement
fuse block needs to have at least 2 inputs; many of the ones sold for stereo
installation and such only have a single input.

> 2) There are two wires that come out of the heater box. Does 
> one go directly to the switch and the other to a ground?  

Should be right.

> There are three prongs on the blower switch, what are the 
> other two prongs for?

One of the prongs should get a green wire that, according to the diagram I
have, comes from the voltage stabilizer on the back of the speedo and gets
power only when the ignition is on.  When the heater switch is turned on, it
connects the two prongs together to supply 12v to the heater motor.  No idea
what the other prong is, my book only shows two of them.  Likely it should
be left open.

Surest way to find out which is which is to use a ohmmeter (multimeter) or a
powered test light.  Look for the pair of terminals that are connected
together (less than 1 ohm or the light comes on) when the switch is 'On';
and not when it is 'Off'.

Randall


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