3 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHdefogger/defrost only blows hot air
Leading reported evidence
Use of the a/c
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
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Suggestion
HOT airflow will ALWAYS defog/demist the windshield interior surface whereas the use of the A/C to dehumidify the system airflow is determined by mother nature.
Leading evidence: 'Use of the a/c' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Use of the a/c' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Use of the a/c as an axillary defog/demist capability
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
There is no IMMEDIATE harm in the use of the A/C as an axillary defog/demist capability, it might actually help if the Rh is relative high.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Use of the a/c
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
HOT airflow will ALWAYS defog/demist the windshield interior surface whereas the use of the A/C to dehumidify the system airflow is determined by mother nature.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
3 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T200546Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
HOT airflow will ALWAYS defog/demist the windshield interior surface whereas the use of the A/C to dehumidify the system airflow is determined by mother nature. With the OAT below about 45-50F the incoming air Rh is rarely high enough to quickly result in a significant level of dehumidification. If the OAT is below ~34F the A/C compressor will be COMPLETELY disabled.
The HOT airflow, additionally, will HEAT the windshield surface thereby reducing the potential for re-occurrence of windshield condensation significantly.
My '01 C4 has switch mounted on the back wall of the console glove box with which I can disable the A/C compressor, open the A/C clutch circuit, throughout the cool/cold weather season.
There is no IMMEDIATE harm in the use of the A/C as an axillary defog/demist capability, it might actually help if the Rh is relative high.
But beware....CAUTION.
If the A/C is subsequently cycled OFF, as is usually the case, the condensate just previously condensed onto the ~10,000 square inches of COLD evaporator vane surface area will now be FREE to evaporate into the incoming airflow. That often results, as the cabin Rh rises, in a quick re-occurrence of the windshield fogging episode.
Best to NEVER rely on the A/C except for actual cooling need or initial cabin cooldown.
Yes, SOP...
But only for the more clever automotive climate control design engineers..which EXCLUDES the NipponDenso and/or Denso US engineering IDIOTS.
When a driver actuates the defrost/defog/demist mode of the climate control system a reasonably intelligent design would operate as if the there is the most DIRE defog/demist need, presume that for whatever reason forward visibility is severely compromised.
NipponDenso, Denso US, automatic climate control designs, once found only in Asian built products, now seem to also dominate the US automotive market. These designs are TERRIBLY, even HORRIBLY flawed insofar as the need to most QUICKLY defog/demist the windshield interior surface once the cabin temperature is within or nearby the selected temperature setpoint.
After years of trying to deal with my '92 LS400's propensity for SUDDENLY/SPONTANEOUSLY fogging over the interior windshield surface without warning. I finally took the climate control computer apart and modified it's defrost/defog/demist mode operation such that with the PB actuation of the defog/demist mode then FULL HEAT and FULL blower speed is called for INSTANTLY.
This is a source reference. Confirm exact model applicability in the original material.
