Hey guys I recently bought a 97 c5 and noticed that to turn the heat on I have to flip a toggle switch I have the digital heat display in the car which is either extremely dim half the time or not even seeable unless you tap on it anyway when you can read the display you turn it up and nothing until you flip the toggle switch even when you shut the car the heat stays on until you flip that switch again any ideas on how to fix this problem back to normal

 

What is this toggle switch? There should only be buttons and ***** to adjust the temp. The dim display is common and easily fixed but that may not be your only problem. Here is a link to the display fix.
http://forums.corvetteforum.com/c5-t...splay-fix.html

 

Sounds like you have some type of a shut off valve on the heater hose. This is not normal, and was installed by someone. If you know how to check the DIC for codes, do so, write them down and post back, looking for C codes on the HVAC, or do a seach for how to? I am betting someone put a cutoff valve in for a reason?

 

What would be the purpose of a cut off valve

 

I can deal with the dim display but what a pita to have to flip the switch everytime

 

Please take a picture of this SWITCH and post it. It not a NORMAL part of the C5 system..

If your HVAC System had an issue with the temp control doors, that may have been a HACk to get around doing the repair the correct way.

READ and POST the DTCs that you have:

READING YOUR Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.

The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect)
3) Press and hold the OPTIONS button
4) While holding OPTIONS, press FUEL button four times within a 10 -second period.

Initially, the on-board diagnostics go into an Automatic Mode which will cycle through each module and shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each module. ( i.e. PCM = 4 codes) If none are present in a given module, you will see No More Codes on the display.

There are two types of diagnostic codes, Current and History designated with a letter suffix, “C” or “H”. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes. More likely it's an indication of an intermittent malfunction.

Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.

Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present; press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles. There are a few body module DTC’s that if set will prevent the module from operating properly. Once the DTC is cleared, the module will return to full function. This is not true for power train DTCs.

If you have never read and cleared your codes, there will probably be a lot of old history DTCs. It is recommended that you clear your codes and see if any come back during a driving cycle. Those are the ones that you need to concentrate on diagnosing.

Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5.

NOTE and a WARNING. You can read the DTCs while the engine is running. I pull mine up all the time while driving.
WARNING. Don’t become distracted while reading DTCs while your driving and cause an accident!!!!! Use common sense and drive safe.

These are some very good C5 Diagnostic Trouble Code (DTC) explanation web sites!!! They also explain how to read the DTCs

Here are some very good sites that explain what DTC mean:

http://www.gearchatter.com/viewtopic11755.php

http://www.obd-codes.com/trouble_cod...d-ii-codes.php

Make sure to include the H or C suffix when you post your DTCs!!

 

After ripping apart the car the switch has two wires goin to passenger side footwell were not wires go into a fuse box were its labeled blower motor guessing there shoul be a fuse there any ideas

 

I have no hvac codes at all some PCM codes and others though

 

Do you have dual zone or manual HVAC?

What number FUSE is it??

Remove the wires and install the correct amp fuse and see what happens.

If it blows, then figure out what component is drawing the excessive current.

When you tell us what system you have, I can provide a schematic.
BC

 

Dual climate the digital one its fuse #49

 

 

Blo/Mot #49 is a 30 amp maxi fuse. The schematics that i have in my collection are for a 99 so the fuse numbers are different.

BC

 

Unfortunately I'm no good with testing wires ill put the fuse in hopefully it won't blow but if it does could this be as simple as a faulty climate control dash I mean the lights are very dim on it

 

Dim lights are a common problem on the displays, and does not affect weather they are working or not. According to my 99 manual, the #49 is blank.
Just curious, going back to you original statement, is the switch for the blower motor?

 

Yes the switch is wired in to we're the blower motor 30 amp fuse would go so after further research am I to assume the blower control module is bad since when the switch is on I can still control heat from climate control if so were is it located is it in the same area as the fuse box I'm in

 

If you have a duel climate control,, the control head will NOT blow that fuse... The MOTOR CONTROL MODULE is most likely bad.

Its mound on the under side of the air box near the blower motor... The blower module pigtail plugs into the motor.

It comes out as an assembly. Yours is digital and expensive... The manual system HVAC uses a resistor module and it is fairly inexpensive to replace.

Heres a picture of the one you have:





If you remove the cover off the module,, this is what is inside of it:





Here is what burns up in the modules when they short:





If you remove the module,, you do NOT need to remove the two screws in the back as theu are slotted. Just loosen them.

Here is the LESS EXPENSIVE manual resistor module (burnt)





BC

 

And is all this under dash on passenger side were I am

 

what years were the electronic vs manual ones?

 

So after further investigation I crawled up under passenger side is the blower control module the piece straight up in corner if yes do you have to take anything out to get at it or just take bolts out

 

Loosen the back two and remove the front single bolt.

BC