I have a '99 Accord with 128,000 miles on it. I maintain it well: everything that the service manual calls for and each time it calls for it. I've replaced the antifreeze and hoses each time and on schedule. This past year (during the cold Jersey winters), I wait for the car to warm up and then turn on the cabin heat. It'll be hot for a few seconds, and then it'll get suddenly cold ! If I just turn the temperature **** (either way) just a hair, the heat comes on again. then, about a minute later, it'll get cold again. If I again turn the temperature **** just a hair (either way), the heat comes back ! This will continue until I've been driving about 10 minutes or so.
Any ideas ?

 

u check the fluid level?-- that happened to wife's car after a recent timingbelt/waterpump change... fluid was below low-- i topped it off-- Whallah!

there are other things to look for like the heater control cable adjustment & such, but I'll let others chime in on this...

 

I'm not an expert on this by any stretch, but if your heater core was bad I don't think you'd get any heat - or you'd have antifreeze on your floorboard. My guess (and this is a guess) would be either low fluid as mentioned above, or a bad temperature ****.

You haven't done any radio work lately, have you? Aren't there little vacuum hoses attached to the temperature gauge? Maybe it came loose?

 

what would the radio have to do with his heater?

 

It's been over 7 years since I've taken the radio out of my '99 LX, but in a couple of Chevy's I've had in the past 7 years ('88 Corsica and '88 Celibrity, commuter cars), both of which I swapped out the radios, the temperature gauge and other dash controls were unplugged when replacing the radio and the controls were plastic vacuum hoses.

I'm just saying, if he's been working in the dash area around these controls, go back and make sure the connections are secure.

 

I suspect it will be the potentiometer (a variable resistor) which works as your temp selector ****. It may be loosing continuity when cold, you move it and it momentarily makes the connection again. This keeps going until it warms up.
I don't believe there to be a cable for this Generation Accords between the Control head and the heater box (unlike prior cases)
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It is all done electronically thru two stepper motors (servo's) (The 'Mode" Control motor) and the (Air Mix Control Motor)
There is still a cable which runs from the Air Mix Motor to the Hot Water Control Valve.
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P

 

Thanks and good try...but my coolant level was fine.

 

to P_Adams: good idea ! ...and with pictures and pricing yet ! Thanks !