My cat 320b has no power to a/c control panel and I don't think it is geting power to half the control module Where could the fault be thanks
Have you pulled and checked all the fuses and relays?
fast_st has a good idea and for better advice it would help to have a S/N. I took a quick look at 320B's in SIS and there are close to 2 dozen different prefixes and that does not count the possibility of several different changes within any one of the various prefixes.
I have changed all the relays and checked all the fuses they are all still good I've change the heater control in electrical box behind the cab but there is a time really in a resistor really not sure what they do
still no serial number?too many differences too guess
Serial number is 5br 01606
As you can see from the images the a/con circuit is supplied from two sources an unswitched power supply and a switched power supply. the unswitched supply is via the 60 amp breaker, the 20 amp fan fuse and then to the a/con controller. The switched supply is via the main relay ,the15 amp a/con fuse and then to the a/con controller I would confirm power at the 6 pin connecter tor at the acon controller on pin#1 green wire and pin #3 red wire,also confirm good ground on black wires at pin# 2 and pin# 6 View attachment 320B SENR9258SENR9258-02_SIS.pdf View attachment 157438 Mark
I thought the power to the a/c control panel was supplied from the control module
John, Just in case you didn't know if you click on the text above the images, the one that starts "320B SENR9258" it will let your down load the full schematic that comes in the Cat service manual. If you have a good PDF file viewer you can use a search feature that will let you trace wires much better. Also the schematic will show a lot of other info like location of components and such. Definitely some thing to save for future reference!
Thanks guys I Will download it And see how it goes If I have any troubles I'll let you guys know thanks
The 15 amp fuse has power going through it But no power to the a/c controller panel
If I'm following this wire (#124 from fuse to controller) right it should be going from the fuse to a 12 contact plug in cab(looks like might be under floor or dash area?) #2 socket in the plug. From there it should go to controller plug in socket #1.( assume that is by the AC unit in cab behind seat?) This wire should be "hot" with key turned on.
Could it have something to do with the time relay or Regulator relay in the electrical box Behined the cab ??
Have you checked out the #124 wire, from the fuse all the way to the controller plug?
Not that exact one but in general all the wiring in under the fuse box and to the controller and underneath the Machine under the cab looks to be in good condition
All I can say is looks don't count for much. You need to confirm that the power is getting from one end of the circuit to the other. Where I worked we had just got a new fresh from Cat 988H and with only 250 hours on it it started setting error codes relating to a sensor for a hydraulic pump. After much checking found one wire in a plug connector had a bad crimp. Same machine at only 90 hours had a non-working back-up alarm that more or less fixed itself by us unplugging and replugging connectors from one end of machine to the next. So just because a harness "looks" good does not mean it is. Not trying to be a jerk but sometimes you need to verify something is working.
I'll echo Ken's sentiments. The only way to check is to follow the power through the system imagining it was water. Start at a point where you know you have power and follow the circuit wire by wire until you find the problem. The "could it be this, or that, or maybe even that" is called fault finding by substitution (aka throw money at it and hope that eventually the problem will go away). If you don't have a digital multimeter that can measure both DC voltage and resistance you need to get hold of one, even if it's borrowed it is the best tool you can have for this kind of work.
S n is 5br 01606
I followed the 124 wire green from fuse to ac unit and is hot when ignition in on