Hey all, first timer here. New owner of an 04 Accord, love the car, but it's got this issue with the cooling fans coming on for like 5 seconds at like 30 second intervals. I haven't timed it exactly or anything, but it seems around 30 seconds to a minute. It SEEMS like the interval has a pattern. But I can't be certain of that.

Anyways, they will go on when the engine is freshly started on a cold day in November in the North Central Illinois, and go off and on, repeatedly the entire drive. The lights dim because of this and the engine idling gets confused by this as well. The fans do not come on while off at all, only while the car is running.

Also, not sure if it's related, but a cold start also holds the idle at around 1500 RPM's for what I would consider longer than normal, around a full 3-5 minutes before it finally settles to a normal sub-1000 range. Once the car is warm the idle is mostly not an issue, but the fan coming on obviously draws a lot of power and causes it to increase for a bit.

The car doesn't die at all, even with the power drain from the fans causing the dim lights and all. It's never dropped to a "low" rpm rate due to them coming on, but it does cause erraticness in the idle.

I've done what little searching I can and things are pointing at the TPS or the CTS-B. Just looking for a little insight as I'm not overly confident in my mechanic diagnostics, and obviously if I can make this a cheap DIY fix, saving money is always a good thing. Maybe if someone has some diagrams that I can peak at as well. I can take things apart and follow directions very well, and I know my way around a toolbox. But I'm hardly mechanically inclined.

Any help would be greatly appreciated.

Thanks!

 

What's the ventilation set at?

With the air directed in the defrost or the floor+defrost position, it runs the air conditioner. But it doesn't turn on the green AC lamp on the dashboard. You can verify this by watching the compressor clutch pulley engage & disengage.

I guess that's the first part, to show that it is (or is not) the AC running. Then look at the idle control with that in mind.

 

Easy test, turn the climate control completely off and see if the fans come on. The idle issue is a bit odd, how many miles on this thing? Does the temp gauge go up to just under half within a 3-5 minutes after start up?

 

Thanks for the replies.

Ahh, now I feel slightly stupid. Guess I should have noticed that pattern that it was only when I was using the defrost. Yeah, I pretty much always have it on the Floor and Defrost.

Is that normal operation for that then? And it's supposed to have that big of a drag on the engine I assume as well... I find it strange that it dims the lights that much when engaging while giving it gas (1.5k-3k RPMs) driving down the road. I'm not used to having a car that basically everything works, so it's probably just me, haha. But, as long as that sounds normal, I won't question it anymore.

With that one pretty much solved... the "longer than normal" high RPM issue, There's 107k on it, Temp gauge seems pretty "normal" to me, I wouldn't say it hits that point at the same rate the idle drops, but it does reach it's normal operating temperature in around 5-7 minutes I would say. All fluids are normal, the temperature doesn't fluctuate at all once it's warmed up and the idle is also normal once it's warm.

 

yup, mine does the same thing with the lights dimming a bit when the fans come on. if you want to tackle it you could try cleaning the IAC valve and the throttle body...it can do wonders for idle performance.

 

Yeah, I was thinking IAC and TPS. Are there some quick and dirty DIY guides out there on this? I'm sure I could just dive in and do this myself, but I'm sure I'll end up doing something the hard way wasting time when it could be done another way and be done in a fraction of the time. So why re-invent the wheel here, ya know? I always end up doing things the hard way. Haha.

Thanks again!

 

is it a 4 or 6 cylinder?

 

Oh, sorry, it's a 4.

 

best way is to remove the throttle body and clean it good with some fuel injection spray cleaner (not carb clean) remove the IAC valve from the throttle body (there is a complex o-ring that seals it up, don't damage it) and then clean that out as well. if you're lucky you can get away without replacing the throttle body to plenum gasket. a bunch of electrical and hose connections, throttle and cruise cables, but pretty easy to do.

 

Cool, appreciate it. I'll probably dive into it this weekend. Thanks!