Chock up another for Ratsun....

[Buzzbomb]

This site is great...

 

For as long as I've owned my 720 (long time), I've had an issue with the heater. It worked great, BUT only worked on HI speed. Kind of a PITA in a cold weather area. Since I received such great advice with my head gasket fix, I figured I'd do a search here and see if I could come up with anything regarding funky heaters. Turns out that others had the same problem, and now my heater is fixed! It works great on all speeds, and is REALLY warm now that I swapped out to a 195 thermostat (I bought a new Beck/Arnley t-stat for $1.95, couldn't resist at least trying it for that price)...

 

SO...FYI for anyone that may search in the future, the 1980 720 doesn't have two phillips screws holding the heater resistor on, but two molded in pegs that push into the heater box. You can get it out just by unplugging it and prying gently with a tiny screwdriver. My top coil, which I belive is the ground (blue.black) was attached to NOTHING. It wasn't broken, it was just hanging there. I actually think it was a factory defect...Anyway, to fix it permanently put a small bolt through the lug, slip the coil wire end over the bolt, put a little nut on, tighten it, and FIXED for about .02 :cool:

 

All hail the search! :lol:

Edited April 7, 2009 by Buzzbomb
Datzenmikes pic...Some 720's have screws

[izzo]

haha

 

Yeah i have that same problem, only works on high. I havent taken the time to fix it because i really dont care at this point. If its super cold out i only use the heater during warm up to defrost the window, other then that i just turn it to fresh air and the wind that blows thru is enough to heat up the cab.

 

I will fix it eventually and put some new seals on the thing to get it working nice again.

 

I used the search the other day to for Dieseling and was able to find a good article on it. Hooray for the search button :D

[datzenmike]

The 620 used the push on type. Maybe the early 720 did too.

 

620 heater resistor:

http://i138.photobucket.com/albums/q251/datzenmike/electrical620heatertwospeedcoil.jpg[/img]"]

 

720 (late) heater resistor:

http://i138.photobucket.com/albums/q251/datzenmike/heater720stuff002Large.jpg[/img]"]

[izzo]

ill have to look for that, i didnt want to yank the entire box out to replace that part.

 

do you have a shot further back you could give me an idea where its at?

 

 

If not its cool ill look around and take a few snap shots when im doing it

[datzenmike]

It just to the left and up from the fan motor. You may have to remove the tray but easy enough to get at. Its right against the hose bellows that connects the fan to the heater body. In the picture, just to the right of the resistor you can see the 'squirrel cage' fan blades.

[Buzzbomb]

Datzenmike is right on...Big surprise, right :D

 

All I had to remove was the package tray, and that was good because I put that back on tighter than it was. Take the tray off, pull the plug off the resistor (large connector w/3 BLUE wires- should be the same as mine), and gently pry it out with a small screwdriver. There's even a few slots along the edge to fit the screwdriver in. My top coil was simply not connected to the brass spade on the inside. You'll know it when you see it if yours is the same. Looks like a factory defect to me...

 

My resistor was like the one pictured with the pegs...Except it looks like that one has two spades and one coil, and mine had three spades and two coils.

 

If you have an extra 5 minutes, fix it. It really is easy to fix and nothing of any effort needs to come off to get to it.

Edited April 7, 2009 by Buzzbomb

[izzo]

ya no doubt having all 3 speeds would be nice

 

 

i did see a new one of these resistors on rock auto!

 

was only 5 or 6 dollars if i remember right. Put some pictures of your truck pls, id love to see it.