Blower Motor kills 4wd cluster.

[Kennytmcp]

Ok now weird right?

98 Jimmy 4wd about 2 weeks ago my inst. Panel went haywire... lights on that shouldn't be, like the charge light even tho the guage still read 14v output.

More interesting, the fuel guage slammed to the bottom... 1/2 tank of gas and the needle drops like a bad habbit.

At the same time my 4wd cluster quit lighting up... and I was unable to switch from 2wd high, to anything else.

And... my blower motor quit working....

My wife in attempt to get heat helped me realize if I turn the control knob off... {not the fan speed as it didnt matter, the control of the ac/vent/blower control} all the controls worked fine.

In the event of testing, each time I engage the control, the 4wd cluster goes out.... then disengage the control and it comes back on.

I pulled the plug on the blower motor, and this quit happening, although the light on the 4wd cluster did dim conciderably.

Thinking I needed a new blower motor, I purchased one at AAP and before I tore the cover out to replace it I plugged in the harnes and tried it...

yup, you guessed it, same problem....

now I am completely lost, I hope one of you folks have seen this before or can help me figure it out.

I have searched through the archives but not found anything definate...

Thanks in advanced, Kold in Kentucky... {lmao}

kk

[MT-2500]

I would go over power feeds and grounds and fuses real good.
Also check amp draw on blower motor and other stuff.
MT

[old_master]

I agree! If all that stuff happened at the same time, you'll be looking for a bad ground. Don't be concerned with the HVAC working properly, it uses vacuum and is not affected by grounds.

[Kennytmcp]

Thanks for the quick reply,

today i went over the connections around the engine compartment, I was unable to see obvious damage or failure.

So I decided to remove the blower control switch and the resistor to do a visual inspection of the contacts and surfaces...

In order to do this I decided to remove the harnes from 4 points of connection. Resistor, some little do-hicky on the wall over the computer, the computer its self, and the blower motor....

I accidently left the key on during this process... but while I was doing this the blower began working...

I turned off the key and re-attached all the connections and it wouldn't work again... so I left the key on and tried to replicate using one connection at a time...

So, eventually I figured out that with the resistor unplugged, I could tap the control switch/relay and the blower would kick on, tapping it again or changing anything on the control panel inside the vehicle would cause it to stop again...

I purchased both the resistor, and relay/switch, (less than 35 for both) and installed them....

much to my dismay and aggrivation,... the problem still exist... only now I cannot even simulate the test described earlier...

I have removed the wiring wrap and am unable to see obvious failures in the wiring...

Please advise... thank guys...

oh, I tried hooking up the new blower again and it still don't change anything...

{i.e. turn on the hvac control and I loose 4wd cluster... and no blower.... still}

[MT-2500]

Ground and power feeds.
It is losing voltage or ground some where.
Get a good volt/ohm meter and go over it.
Good luck
MT

[Kennytmcp]

Well, I traced and checked {removed/cleaned/reinstalled} all the grounds.

trying to do this on warm weather days has really taken me a while to get it done... Guess what... same problem... bla bla bla...

I got tired of screwing with it and took it to a dealer... turns out 1 column of my fuse box was not getting power... they replaced the ignition box in the steering column and fixed it... diag, parts, and labor, $270

damn i miss my 78 camaro, i could really work on it.... {lol}

l8r

[MT-2500]

Glad you got it fixed and thanks for posting back how it went.
MT