new mazda b2600

just bought a 2600i 4x4 1989 and so far its been a pretty good truck for what ive needed, however there are other fixes i have already done but this one is driving me nuts.

the heater doesn't turn on when i turn it on, and the windows fog up bad! what could it be? I've checked the circuit breaker and its fine, fuse Isn't blown but it could be bad wither way, can i use a multimeter to check it?

also the 4X4 light is always on, I've checked 4wd and it works, i bought the truck from a guy who owns/manages 3 Aamco transmission shops and he said the tranfer case and transmission were just rebuilt, what could it be?

and last the temp gauge doesn't work either but i think i may have fixed it but not sure yet, maybe give me some pointers, thanks!

Well, most likely the blower motor is bad or frozen up. Common problem if the the cowling leaks and gets water into the blower motor housing.

Check that you are getting 12 volts to the fan by unplugging the connecter. If not, then you'll need to work backwards and find out why you are not getting 12 volts. You probably are.

If you do have 12v getting to the motor, pull the blower motor and make sure it turns freely. If not, then it's frozen and will need repair or replacement.

If it turns freely, then connect it to a 12 volt source and see if it runs. If not, then the motor is bad. If it does run (and assuming above that you had 12 volts getting to the motor while installed), then your problem is likely a bad ground...meaning the resistor or possibly the fan speed switch. If your resistor has an extra loop/jumper wire, make sure it's plugged in. Even if one of the resistor elements is burned out, it should run on position "4" since it doesn't flow through the elements. But it is possible that resistor could still be bad.

If not the resistor, then it's probably the fan speed switch since it makes the contact to ground. If you have AC, you can do a test to see if the compressor will come on in any or all of the fan speed positions. If it does, the fan speed switch is probably good.

yeah it was the blower motor, put a new one in and it works, although it was such a pain to put it back in!!! now just gotta figure out the rest, 4x4 light, and the temp sensor

My "trick" is to unbolt the ECU from the firewall and use 1/4 inch drive 8mm socket and extension. Some have longer wires than others, so easier to connect/disconnect.

Post it up!

4x4 light not going out? The most common problems on the 4x4 are:

1. leaking/cracked/broken/missing vacuum lines that control the RFW actuator
2. damaged wires to all of the sensors on the tranny/transfer case/front diff
3. solenoids that control that vacuum.

Then there is the actuator itself, the switch, and the computer that controls it all (a 4x4 system computer, not the main engine computer.)

What's up with the temp sensor? The one for the gauge? or the engine computer?

it could be the vacuum lines because they are pretty old and cracked, but the actual 4wd works.

today i jacked up each wheel individually and spun them while in gear, both spun freely while in 1st gear and in 2H, but then when i did the same test but in 4H and in gear the wheels locked up signifying that its not engaged all the time PHEWW! is that a proper way to test? i tried doing burnouts while someone was watching but it was hard to distinguish any wheel spin so i chose that method.
it could also just be an electrical issue because there is another light "neutral" that is suppose to light up but wont no matter what, and also...

im beginning to think the temp and gas sensors are wacky. like the other day i got about 6 gal of gas on top of the 3 i already had so 9 gal out of a 12 gallon tank, means i should have about 3/4th of a tank, but the hand never went past the middle line, and it sat there for almost 50+ miles! i thought i was getting excellent mpgs! but after that the needle was dropping faster more consistent, and the temp sensor is the same way, it raises but only a certain amount...

im wondering if the gauges hands are too low, that when they start rising they are actually below what they are suppose to be, like a speedometer that reads 5mph slower than what your actually doing... anyone have any pics of a dashboard cluster with the engine and electricals off? i think mine at rest are below the stock limit if that makes sense


Im thinking the electrical problems are all tied together somehow

Fuel sender issues on these are common as the trucks age.

Senders are definitely a problem. But there is also voltage regulator in the cluster that generates a reference voltage for each.... albeit a different voltage for each. So it's possible there is a problem with that too. Pull the connecter on the single wire temp probe on the thermostat housing and check the voltage with the key in the "ON" position. I think you should have around 7 volts. If it's way off, the the regulator is probably bad. If it is 7 volts, then it's your sender.

As for the RFW, you need to fix (probably replace) all the vacuum lines if they are original. Also, check-out the harness and neutral switch.

so today i went under the truck and i think i found the vacuum lines but i wanna make sure its them, theres 2 of them and they travel up into the motor somewhere, wasnt able to find out where though because its too hot out but where do they go?