blower function ok except for fastest (4)

[wouter]

Pontiac TransSport 1995 blower does function except for the fastest opton. Then it does nothing. Ive located two relays, one near the steeringcollumn and one near the glove box. The look OK to me. Can anyone tell me where to from here?
Thans in advance!
wouter

[LMP]

The one near the steering column is the rear heater relay
the one near the glove box is the low speed relay

THe High SPeed Relay in located on the firewall, on hte engine side

www.avigex.ca/xport/heaterrelay.jpg
www.avigex.ca/xport/hvac_diagram_front.jpg

[wouter]

Originally Posted by LMP

The one near the steering column is the rear heater relay
the one near the glove box is the low speed relay

THe High SPeed Relay in located on the firewall, on hte engine side

www.avigex.ca/xport/heaterrelay.jpg
www.avigex.ca/xport/hvac_diagram_front.jpg

Thank You!
I've replaced the relay on the firewall: problem solved!!
(Yesterday i've removed lots of parts from the dashboard, finding the mentioned relays. Thanks again!)

[willisaon]

I have the opposite problem on my '97 Transport in that speeds 1 to 3 do not work while 4 & 5 are OK.

Problem is I can't locate the Low Speed Relay near the glove box. I have removed the glove box and found a relay up underneath close to the firewall and mounted in a chassis that accomodates 2 relays (I have just one). Is that it? (P/N 12088592 or AR169 from NAPA).

Thanks in advance

[LMP]

Then your problem is probably the blower motor resistors that are used for lower speeds. THey are also on the firewall just beside the high speed relay
www.avigex.ca/xport/heaterrelay.jpg

[treecutter]

Originally Posted by wouter

Thank You!
I've replaced the relay on the firewall: problem solved!!
(Yesterday i've removed lots of parts from the dashboard, finding the mentioned relays. Thanks again!)

What is the part number for the high speed motor blower relay? My local NAPA dealer does not carry it based on the description. I have a 1992 Transport. I've searched several parts places on the internet but the parts description is too cryptic for me to know I would be ordering the correct part. Thanks

[LMP]

BOSCH 12077864 800 on my '93

[ciras3]

Just had the same problem happen on my 1995 Trans Sport. Looked this up on the forum and was able to fix it within an hour of finding this thread. Part number for my 1995 is Bosch #12077864-800 and was $12.99 at VATO ZONE. You could see inside the old relay where it had fried out. A quick fix.

[ciras3]

Originally Posted by ciras3

Just had the same problem happen on my 1995 Trans Sport. Looked this up on the forum and was able to fix it within an hour of finding this thread. Part number for my 1995 is Bosch #12077864-800 and was $12.99 at VATO ZONE. You could see inside the old relay where it had fried out. A quick fix.

Since I wrote this and replaced the blower relay, the new one fried out 1 1/2 months later. I'm glad that I saved my receipt as it had a one year replacement warranty. Just wondering if anyone else that had replaced their blower relay had the new replacement one burn out also. I wouldn't think there is anything wrong with the wiring in my van since the replacement relay worked for a month and a half before shorting out. The new one is working for the past 2 weeks. Any ideas ?

Thanks in advance

[LMP]

I'm just curious to know what part of the relay fried : it is either the contacts (which can be related to high current drawn by the motor or by insufficient contact rating) or the coil itself....which is faulty relay coil that's all. ON HIGH, the motor current is around 25 amps, which is a lot of current and that needs high quality contacts otherwise they will melt away. But blown coil can be due to DC pigtail effect (voltage spike at turnoff) if there is no diode protection ..but the coil should either include the diode (then coil polarity is only one way) or one could add an external diode. But anyway, the car was built so it should work normally without any modification..

[ciras3]

Originally Posted by LMP

I'm just curious to know what part of the relay fried : it is either the contacts (which can be related to high current drawn by the motor or by insufficient contact rating) or the coil itself....which is faulty relay coil that's all. ON HIGH, the motor current is around 25 amps, which is a lot of current and that needs high quality contacts otherwise they will melt away. But blown coil can be due to DC pigtail effect (voltage spike at turnoff) if there is no diode protection ..but the coil should either include the diode (then coil polarity is only one way) or one could add an external diode. But anyway, the car was built so it should work normally without any modification..

Hi,

Not sure how to tell what is causing the failure. If I take the old blower relay and look inside at the male contacts there is melted plastic at the base of the top contact (12 o'clock) on the right side where there are three male contacts. There are two contacts on the left side and three on the right, if you look inside the relay and have the numbers where they are printed right side up. On the right side (three male contacts) the bottom number is 85, the middle number is 87, and the top number is unreadable because of the melted plastic at the base of that contact. This is where both blower relays have failed.
I would also like to take the time to thank you for all of your hard work helping people out on this forum. I'm simply amazed that you take the time to not only answer questions for Trans Sport owners, but take the time to post pictures, diagrams, etc. I really do appreciate that there are people out in this world like yourself that make this forum what it is for others.

C. Smith
Cleveland, Wisconsin