What is this part? (from an old climate control circuit)

[Genestealer]

Need help identifying these 2 greenish rectangular components. This is a circuit from a 1970 cadillac climate control. Can anyone also recommend what new parts to buy to replace them?
One of them is broken, here's how it looks like.



I suspect the other might be fried too.


Hard to read what was written on the small part.

 

[shrtrnd]

They're called 'Power Resistors', readily available from electronics supply stores.
The resistance value and tolerance are written on them:
50 Ohms at 10% tolerance
Can't see for sure, but the small one looks like 5 ohms at 10% tolerance.
These are an old (dependable) style, but you should be able to Google the long
number, and get the manufacturer specs (for wattage).
I'd do it, but I have to go to work now.
If you can't figure it out, somebody here will probably help you soon.
The resistors are relatively inexpensive (a few bucks for high wattage), so if that's
the only problem, don't worry.
If you take the board into an electronics parts supply store, the salesman can point
you in the direction of an equivalent, if you're in a hurry (and can solder).

 

[davelectronic]

Components

Hi there Genestealer.
Those are power resistors, one looks like 50 ohms, another has 10% on its, thats its tolerance under operating conditions in temperature of the resistor, for a power resister to end its life like that its either damp moisture, or intense heat, looking closely at the base of the damaged resistor it looks like charring, darker discoloration, but from the pic's its hard to tell, any way something failed to allow the resistors temperature to rise out of its rated temperature region, although some damp might also be responsible, it hard to tell from pic's.
Your be able to get the parts i expect, but if the unit works again is any ones guess.
And if its a mains device, and that is heat damage, i dont think i would take the risk of repair, more like replace the whole unit with a new one. Dave.
PS sorry a car, ok you need to find the power rating of the damaged resistor, some research on the vehicles data might help, its got to be the correct resistance and power rating, there is also what looks to be a large transistor, or a thermal package, you wont know the extent of the damage until you replace the resistor and try the climate control.

 

[daddles]

They're also called "sand resistors". You can find them for a few bucks each at Radio Shack stores (and any electronics distributor).

 

[Resqueline]

Even if it's physically broken it need not be electrically broken. Measure them for the correct resistances mentioned above.
If they're ok and the control doesn't work there are many other things to check; the two transistors on the board, and any sensors & solenoids.
The wiring diagrams should help. The board looks very soiled btw..

 

[Genestealer]

Thanks all for replies.
I haven't been able to test the climate control, AC is disconnected so it blows only warm or hot air. I was just disassembling the dash to see what's in there and found the broken resistor.

Yes it's most likely a moisture damage, the car had a problem with leaky windows, and a lot of steel parts behind the dash are covered with surface rust. I cleaned the circuit board from the dirt, it looks pretty clean now and seems like there is no heat damage.
Just measured them with multimeter, smaller reads 5.7 Ohms, larger one 32 Ohms.
About getting a new circuit, I have no idea where can I find one. I can solder so I'd rather replace components.

 

[davelectronic]

I would go with 5 ohms and 30 ohms, usually they are a little over when reading with a meter, new ones that is, i would hazard a guess at 10 watts the small one and 20 watts the big one, but there must be a schematic on the circuit some where, if the motor is a vintage try those sites, or if more current send a few emails to dealers or restorers. Dave.

 

[Resqueline]

They are stamped 5 & 50 ohms. The bigger one is probably just wired in parallel with something else. I guess they're 4 & 10W.
I wouldn't bother replacing them (yet) until I had tested more of the system. The resistance readings also seems ok to me.

 

[Genestealer]

Found a new board, but it's expensive, $150.
http://www.oldairproducts.com/catalog/gm/1222253/switch-p-30082.html

Will probably go to local Electronic Supply Center tomorrow and see what they have.