Heater Fan?

[deeb]

ok, hopefully this is the last issue for a while (fingers crossed)

98 disco 1- my heater fan doesnt blow.

i can feel the heat coming out of the vents, but the fan wont blow.
the a/c fan blows when i have the a/c button pushed, but no fan when its not pushed.
are the a/c and heater on the same fan?

i looked at fuses on drivers side, no blown fuses there...any other ideas?

hoping i dont need a heater core!

thanks
chad

 

[greg409]

The blower for the heater or a/c is the same blower.

If you have multiple blower speeds when a/c mode, then your blower is ok.

it has nothing to do with the heater core. (besides, you said you can feel heat when driving, which is good.

I'd check (or maybe someone can clarify) if your '98 has a temp switch which keeps your blower off in heating mode until the engine starts to warm up.

If so, the switch may be bad? (my '97 does not.) - my money would be on a fuse tho'

luck,greg

 

[greg409]

I went back & looked @ my rave cd,

It appears that your '98 & my '97 are the same.

I didn't find any engine temp switch that would keep your blower off until warmup.

It also doesn't appear that the circuits go thru' the ECU (a good thing in my book)

If the fan speed control works only in a/c mode, then I'd pop the switch panel out & start checking with a volt meter.

See if the switch is live only when you press the a/c button?

luck,greg p.s. - I've found that by leaving these little quirks alone, it prevents my wife from driving my truck!

 

[deeb]

ok, update.

there is no operating fan in the front. the rear a/c fan blows.

the fuse under the steering wheel looked good as did the big fuse under the hood. i pulled it anyway, ill try a new one.

is there a relay under the glove box?

i tried my test light on the plug for the blower. no power. if i keep chasing wires back wheres my next place to look?

thanks

 

[joey]

If the front fan is not working at all it could be the fan switch, then tend to go bad... you can try changing speeds and see if that helps.

 

[deeb]

If the front fan is not working at all it could be the fan switch, then tend to go bad... you can try changing speeds and see if that helps.

ive tried all speeds and all settings...no dice.

no relay?

thanks
chad

 

[joey]

I don't recall a relay on a D1, without looking through the electrical manual.... normally it is the switch that goes bad.

 

[greg409]

deeb -

I'm sure by now you've downloaded the free rave cd.

So, go to -discovery1 - electrical troubleshooting '97-'99 - circuits - K1 blower controls - circuit operation.

You'll read a lengthy detail of what relays & cicuits the voltage path needs to operate front or rear blowers.

(I can't type & I'm lazy)

luck,greg

 

[deeb]

ok- so i'll go in after that relay and blower motor switch this afternoon. any ways to test these things out? test light?

 

[greg409]

since you're looking for voltage at this time, any decent $5-10 testing light would be a good start.

Mine's a 70's vintage snap-on (looks like an icepick) with a 6' lead and alligator clip

a good vom meter is great but you can't always read the display when you're on your back under the dash.

luck,greg